- Email: [email protected]
Correlation of some physical and chemical properties of moldavites
Geochimica et Cosmochimica Acta 1984, Vol. 28, pp. 783 to 791. PergamonPrea8Ltd. Printed in Northern Ireland
Correlation of some physical and chemical properties of moldavites VLADIMIR
BOU&KA*
and PAVEL
POVONDRA~
Abstract-Relations of chemical composition, trace-element content, specific gravity, refraction and microhardness of moldavit,es, selected according to colour from several to the colour shade show that colour is a more important guide to their physical and properties than locality. Seven samples selected according to cotour from a small Dukovany (Moravia) exhibit a wide range of properties.
index of localities, chemical plot near
INTRODUCTION THE study of a large number of moldavites shows that their colour ranges from green to brown is essentially five shades: pale green, light green, bottle green, olive green and brown. One additional colour does not chromatically fit into this basic sequence-a relatively rare special “poisonous” green shade. The statistical study (FAUL and BOU~KA, oral presentation, 1963), has shown that some colours are more common in some areas than in others, but that essentially all colours can be found in most localitites. The previous opinions that colour is typical of locality are not confirmed. Brown and generally dark moldavites are not typical only of Moravia, although they clearly predominate there, but they Jso are found on the opposite end of the moldavite belt in Tgebanice, the westernmost moldavite occurrence in Bohemia, as well as in Vr&bhe, Ndchov, T$n and Vltavou and elsewhere. Green and light-coloured moldavites, on the other hand, also occur in Moravia. We have selected seven samples in the six colour shades for geochemical study. The colours were selected visually and confirmed by spe&ral measurements. The samples are listed in Table 1. Table Designation of the sample and of the eolour shade 1
2 3 4a 4b r
z Note: Muzeum,
1. Colonr scale and locality
Locality
of the samples
Colour
studied
Note
Radomilice Koroseky
pale green light green
Tir&bae PiCchov Netoliee Slavice Xetolice
bottle ._ green olive green olive green brown “poisonous” green
I
visually
fully identical
colours
Setjs of moldavite specimens arranged in this colour scale are on deposit in the N&rod& Prague and the U.S. National Museum, Washington.
* Department of Mineralogy, Geochemistry and Prague, Czechoslovakia. t Department of Analytical Chemist’ry, Czechoslovak slovakia. 783
Crys~&llo~aphy, Charles University, Academy
of Sciences, Prague,
Czecho-
VLAIXMIE
784
and PAVEL POVONDRA
&X&A
On these seven samples we have measured the density (Table a), index ot’ refraction (Table 2), light absorption (Fig. I), microhardness (Table 6), major and trace element content (spectrogra~hi~~ll~-Tables 4 and 5), and major corn~~o~l~l-lts Table 2.
W’t+ chemical annfyses of the molda,vites studiPtl
i:_%
1 Radomilice SO, TiO, Al,03 Fe,% Fe0 MgO cao N&,0 KZO
c pl.(A.Naf sp. gr.
~_ 81.52 041 7.99 0.06 1.02 1.87 1.37 2.43 3.23 99.90 1.4838 2.294
Koroseky _~._ .-__ 80.48 0~40 9.33 rt.21 I .:14 3.l.i 2.06 0.5 I 3.33 99.81 1.4875 2.317
3
4a
4b
\-r&bee --.-79.10 0.57 9.75 0.07 1.52 1.98 2.89 0.69 3.4i
n‘echov
XTstolice
81.06 0.52 9.04 @30 1.39 1.71 2.06 0.44 3.32
81.28 0.60 9.05 0.27 1.45 1.67 1.71 0.56 3‘33
99.84 1.4887 2.323
99.92 1~4852 2.322
100.04 1.4911 2.331
99.95 I*4918 2,338
99.x7 1.4966 2.370
(by wet chemical analysis-Table 2). In addition, Ing. K. Soukenik has kindly permitted us the use of chemical analyses of seven moldavites from Dukovany, Moravia, shown in Table 3. Soukenik’s samples were all found within an area of only 100 x 150 m, yet they represent the complete range of colour except for the “poisonous” green. Table 3.
SO, Al,% Fe303
Fe0 E/In0 cao MgO Na,O K&’
Quantitative chemical analyses of moldavites from Dnkovany ail collected from essentially the same spot,
_I brown
11 brown-green
111 browll-preen
IV olive-green
V green
75.0.!? 13.74 0.09 3.2s 0.11 2.29 1.55 o-50 3.13
75.90 12.09 0.26 2.41 0.09 2.69 1.95
75.72 13.14 0.18 2.7r,
76.78 12.00 0,57 2.30 0.13 1.49 1.58 0.80 3.66
77.60 ll*Ob 0.46 2.16 0.07 2.55 1.85 1.08 2.83
99.74
99‘38
99.31
99-54
0.89 3~50
0.09 2.12 1.62 0.73 3‘42 --..-_-_99.77
(Moravia).
\‘I green
-.
VII light, preen
77~52 10.92 0.72
80.10 10.03 0.70
I.75 0.07 2.72
0.04 2.20
I*60 0.78 3.42
1.38 u.75 3.X)
1,a:!
99.82
RESULTS
All samples were tested for uranium oontent by luminescence analysis. The sensitivity of the method is 0-z ppm and all but two samples gave negative results in three ohecks. Only the samples from Net&ice showed a trace. Light-absorption curves, measured on plates 2 znm thick in the visual spectrum are shown in Fig. 1. The shape of the curves is characteristic of glasses except for a higher absorption in the red end (right side). According to COHEN (195&j, the
Spectrograph
Radomilicc 1 Koroseky 2 Vr&bae 3 N&hov 4a Sotolice Ib Slavice 5 Xetolice 8
Locality and No.
Spectrograph
KSA 1.
0.0056 0.0084 0.0094 0~0090 0.0074 0.0074 woo.i7
Rb%
Al, Fe, Mg, Ca, K -41, K, Mg Fe, Ca
Al, Fe, Ca, Mg, K Al, Fe, Ca, Mg, K Al, Ca, Mg, Fe, K
sa
Sa
_ Xa
Na
N&
Ti Mn Ti
Ti
Ti Mn Ti Mn Mn
Ti, Ca, Mn, Na Na Ti Mn
Al, Mg, K, Fe
Al, Ca, Mg, Fe, K
l--O.1 y0
> 1e/e
Ba 31n
Ba
Ba
Ba, Pb, Zn Ba
Ba
O.l-0.01%
V, Ue Sr, V, Sr, V, Ni, Zn, Xi, Cu,
B, Cu, Zn, Cr,
0.0028 0.0026 0.0026 -: 0.001 -:a~001 *: o*oo 1
0~0019
CS%
pb% 10.001
Ga%
n.on1
CU%
i 0~001 < 0.001 .; 0+01 tWX11 -:O.OOl -r-o~oOl -. owl
Ag%
0.01
zn %
0~005?.l.
0.0029 0.0030 0.0025 0.0024 0+)028 0.0017
0%
0.0020 0.0020 0*0019 0.0019 0~0020 0.0018 0.0023
Ni 0%
Co, Ag Pb Ag, B, Co
__
MO %
studied
Ga, Cr, Sn, Pb,
Xi, B, Ga, Co,
0.0021 0.0024 ct~OOZ*~ 0.002,5 W002d 0.0028 0,002,i
I7 %
Li Be, Y Ga, Y Be, Li
Pb
Co%
Sr, Pb, Th, Co, Mo, Li Pb, Y Li
V, Ni, B, Ag, Be, Cu, Ga, Co, Cr, Ba Sr, Cu, B, Zn, Ag, V, Ni, Cr, Ga, Co, Be Sr, Cu, B, Ag, Co, V, Ni, Ga, Be Sr, Cu, B, Zn, Ag, V, Ni, Cr, Ga, Co, Be Sr, Cr, Cu, Zn, A,g, Rb Li, Y Li Pb, Y Li, Y
?
to.01 y*
analyses of moldavites (optical spectrograph)
Table 5. ~uax~tit~~ti~,e sp~~t~ograph~c analyses of some trace elements in the moldavites
Zeiss Q 24.
Xi
Si
SIavice
6
Si
Netohce 4b
Netolioe
Si
Ngchov 4a
5
Si
VrabFe 3
Si
Si
1
> 10%
Koroseky 2
Radomilice
Lot. and No.
Table 4. Semi-quantitative
786
VLADIMIR
BOUSKA and PAVEL POVONDHA
Table 6. Microhardness of the moldavites, measured by apparatus according to HANANIAN, model 13 32, and special objective Apochromat 0.95 (Zeiss, Jena) Hm Locality Slavice K&hov Hlavice Koroseky Radomilice
(lolor r, 6 4 2 1
(g/P2) 916 1001 1099 1211 -1211
colour of tektites is primarily due to absorption by iron, trivalent in the violet end and bivalent in the red end. The moldavite from Radomilice (No. 1) is pale green and has a low content of iron. Its curve also shows only a slight rise toward the red and almost none toward the violet end.
Fig.
1.
Light
absorption of 2 mm plates cut from the specimens Table l), plotted as a function of wavelength.
studied
(see
STAIR (1955) writes that the colour could be caused by combined absorption by iron, nickel, chromium and manganese oxides. In our samples, trivalent iron is present only in subordinate quantities, compared to FeO. Therefore, to express colour as a function of iron content better, we recalculated the iron contents to ferrous oxide (Fig. 2). Except for the “poisonous” green sample (No. 6, N&lice), we obtain a close relation between colouring and iron content. Also remarkable is the agreement in recalculated iron content of samples 4a and 4b (NGchov and Nettilicte) both of which are of the same colour (olive green) but come from looalities 40 km distant from each other. The “poisonous” green sample from Netolice (No. 6) shows a steep rise in absorption toward the red end but shows relatively low iron contents. Its behaviour is Apart from the slightly higher anomalous with respect to the entire sequence. content of nickel, there is no other fact to explain its intense green oolour.
Correlation of some physical and chemical properties of moldavites
787
% 2
1
ZFe 0 Fe 0 I .
i
0
-_----1 L-
Fe203
____.
f
2
3
4b
4%
d
6
Fig. 2. Bivalent and trivalent iron content (solid lines) and summary iron content expressed as Fe0 (da,shed line), of moldavites studied, plot&d as a function of colour shade.
Perhaps the high content of alkaline earths and the deficiency in potassium could have combined to enhance the influence of colouring agents present in small amounts. The moldavites from Dukovany analysed by Soukenik (Fig. 3) show the same relation between Fe0 and colour, but his colour scale differs slightly from ours. The silica content in his sample clearly falls with increasing iron content. Molu’avifes -Dukovany
1
2
3
4
5
6
7
Fig. 5. Silica and iron contents of moldavites collected from a 100 x 150 m plot near Dukovany (Moravia), plotted as a function of their colour shade, after Soukenik. Note that Soukenik’s colour scale has seven steps from green to brown and does not include the “poisonous” green. The absorption curves of our samples also show slight irregularities in the This phenomenon is unexplained for the vicinity of 500 and 640 m,u wavelengths. time being. Relation of indices df refraction to densities confirm the seatements of JE~EK and WOLD&KX (1910), TILLEY (1922), PREUSS (1935) and SPENCER (1939) that the
\jLADEMilt ~OU&CA and PAvEL
788
POVONDRA
index of refraction of moldavites i8 an approximately linear fu~ctiol~ of density, as shown in Fig. 4 which includes all presently available data. !lTheindex a,nd den&y are roughly determined by the summary content of alkaline earths and iron.
Fig. 4.
Index of refraction VS. specific gravity of moIdavites. available data are shown.
All presently
% 4.
CC0
2’
a
iii& . Fe, 4 6
.W
40 46 5 1 2 3 Fig. 5. Chemical composition of the moldavites stndied vs. their colour sha,dr.
On Mohs’ scale, the hardness of moldavites falls between 6.5 and 7. Moldavites being essentially silica glass with 20-25 % of other oxides added, it would be expected that those higher in silica also would be harder. MoldaviteN with the higher silica contents are usually lighter in oolour so that one may compare the hardness of moldavites with their oolour (Table 6). The sample from Radomilice (No. 1) showed a variation in microhardness and the average value is reported. No such variation was observed in the other sample. Table 7. Specific gravity, index of refraction, iron content (expressed as FeO), and stunmary content of alkaline earths and iron of the samples studied SP. gr.
n@ h‘a)
ZF&
2.294 2.317 2.322 2.323 2.331 2.332 2-370
1.4838 1.4875 1.4862 1.4887 1.4911 l-4918 l-4956
1.074 1.53 1.69 1.66 1.58 2.08 l-31
ZFeO, MgO, CaO 4.314 5.74 5.07 5-43 6.45 4.83 7-86
NO.
1 2 4b 4a 3 5 6
Correlation of some physical and chemical properties of moldavites
789
The major-component contents (except for silica) are given in Fig. 5. It shows that TiO and K,O are essentially constant over the entire colour range and the remaining components vary only slightly in the green-brown sequence. Marked irregularities appear in sample No. 6, the “poisonous” green one. It is understandable that variations in the content of the alkaline earths would be reFigure 6 shows the almost mirrored flected in changes in the alumina content. courses of the sums MgO + CaO + Na,O + K,O and TiO, + Al,O,, manifesting the mutual influence of acid and basic components.
f-l
_I-:---:-: dl
6
O+CaO
f f a#+&0 zTiO2 +A/20J
ro.i 9
7 6
Fig. 6.
i
2
3
40
4b
5
6
Siunmary content of alkalis plus alkaline earths and alumina plus t,itania, plotted against colour shade.
Our results do not quite support COHEN’S (1962) conclusion that silica content of moldavites tends to decrease from west to east. Soukenik’s analyses of the Dukovany moldavites, all essentially from the same spot, still show a wide variation in silica content (Fig. 3). Acknowledgements-We are indebted to 1)r. Z. SULCEK of the Central Geological Survey in Prague for the use of light absorption apparat(us and to B. RYBAKOVA and M. MIKSOVSK+ for making the spect,ral analyses. We thank A. BL~~ML of the Rudne doly, Pfibram, for the microhardness measurements and INC. K. SOUDEN~K of Pierov for the use of his analyses of the Dukovany moldavites. Prof. H. FATTLassisted in the preparation of the English manuscript. REFERENCES BARNES V. E. (1940) North American Tektites, pp. 477-656. University of Texas Publications 3945. JJECK R. (1910) Uber die in Tektiten eingeschlossenen Gase. Mber. Dt.sch. Geol. Ges. LX II 240-245. BRUN A. in R. Beck (1910). COHEN A. J. (1958) The absorption spectra of tektites and other natural glasses. Geochim. et Cosmochim. Acta 14, 279-286. COHEN A. J. (1959) Moldavites and similar tektites from Georgia, U.S.A. Geochim. et Cosmochim. Acta 17, 150-153. COHEN A. J. (1960a) Trace element relationships and terrestrial origin of tektites. Nature, Lond. 188, 653-654. COHEN A. J. (1960b) Germanium content of tektites and other natural glasses. Implications Report of the Twenty-First Session of the International concerning the origin of tektites. Geological Congress, Norden, Vol. l., pp. 30-39. Berlingske Bogtrykkeri, Copenhagen. COHEN A. J. (1962) Asteroidor Comet-Impact Hypothesis of Tektite Origin I. The Moldavite Strewn-Fields and the Niirdlinger Ries (Ries Kessel) Crater. Mellon Institute, Pittsburgh, Pennsylvania.
790
VLADIMIR
BOUSRA
and PAVEL PO~ONDRA
DUBEY S. V. in J. Oswald (1942). DVO~SEPI?. (1883$ Die am Iglawaflusse abgesetzten Moldavit-Quarzgeralle. Programm tirs Gymnasiums in Trebitsch, pp. 2-17. EE~~ANNW. D. (1960) Nickel in tektites by activation analysis. ~eoc~~~. et ~~~$?~z,oc~:~~t~,. ._I ~trr
19,14S-156. EH~N
W. D. and KOHMANT. P. (1968) Cosmic-ray-induced radioactivities in mrteoritcs 11:
AlaB, BeXo and Coao in aexolites, siderites and tektites. Geochim. et Cosnaochim. Arta 14, 364-379. ERDMANNL. 0. (1832) Jahrbuoh fur technische und okonomiecheChemie. Leipzig. FRIED-N I. (1958) The water, deuterium, gas and uranium content of tektites. &o&m. t‘t C~c~~~. Acta 14, 316-322. GENTNERW., LIPPOLT H. J. and SCHAEFFER 0. A. (1963) Argo~b~timm~g of Kaliumminewlien XI: Die Kalium-Argon-Alter des Gliiserdes Nordlinger Rieses und der bohmisch-mahrischen Tektite , Geochim. et Cosmochim. A& 87, 191-200; also A. J. Cohen (1962). H~BERMANNJ. in F. Dvorsk$ (1883). HANAMANNJ. (1893) 0 povaze Eeskeho vltavinn. Casopis pro prfimsyl chemickJi. C. I I.. rok III., p. 365-366. HAUERV. K. (1854) in Arbeiten in dem chemisehenLabora~rium der k. k. geologi~hen Reichsanstalt. J. 6. GeoE.Be&&son&.(~~~~u~~) Wie% 4, (VII} 868-869. JEZEK B. and WOLD~ICH J. (1910) P?isp&vek k IeSeni otazky tektitove. Rozpravy Eeske akademie, roe. XIX., tf. II., E. 30. JOHNv. C. (1880) in K. v. Hauer (1880) Bouteillensteinvon Trebitsch. l’erh. &ol. Reirhsl An& (StAnst) Wien 16, 282-284. JOHN v. C. (1889) Ueber den Moldavit oder Bou~ille~tein von Radomilic in Biihmen. J. 0. til. Redbait ~R~~~~~t) Widen Z3@,473-476. JOHNv. C. (1899) Ueber die ohemischeZusammensetzungder Moldavite. t’erh. GeoE.ReiehsAn& (St&&) Wien 6,7, 179-182. JOENSENA. (1906) Beitriigezur Kenntisn natiirlicherund ktinstlicherGliiser. ii’ck. Phys.-f&t~. GM. Kon@~&. XNII, (II) 105-110. KLAPPRO~~M. (1816) Beitriige zur chemisehen Kenntnis der Minearlien. &faguz. d. #es. d. No&m. ~~e~~. Bert& (1795-1815). XZINOV E. L. (1958) Some co~ider~~o~ on tektites. Geoohim. et ~o~~~rn. AC& 14,25S-266. Lac~onr A. (1932) Les Tectites de I’Indochine. Arch. Mw. Nat. Hi&. 6, Serie T. VIII. 193-236. LUDWIUE. (1910) in F. E. Suess (1914). M&sONB. H. (1959) Chemical oomposition of tektites. Nature, Lond. 199,254-255. &%ALYouGA D. P. (1949) The cognition of the nature of tektites. Meleoritilca6, 92-100. NOV&?EKR. (1932) Chemicky a fyzik&lni tizkum n&ktejrch vltavinfi eeskych a moravsk&h. Rozpravy II. tf. Ceske akademie, roe. XLTI., C. 31. OSWALDJ. (1942) Meteorioke &lo. N&l. 6esk4 akad. v&d. a um&ni. Praha. PANETRF.,PETE~EN K. W. und CHLOUPEK J. (1929) Uber den Helium-Gehalt von “Moldaviten“ und ki.instliehenGl&sern. VI, Mitt&l. Ber. Citem. Ges. 68, 801-809. PINSONW. H. JR., HERZO~L. F., FAIRBA~RN H. W. and CORMTE~ R. F. (1958) Sr/Rb age study of tektites. Geochim. et Coemochim. Acta 14, 331-339. PZEIS K. in J. Oswald (1942). P~EUSSE. (1934) Chrom und Nickel in Tektiten. N~~~~8s~~~~n @, 480. PREUSS E. (1938) ~pekt~~nal~~he Untersuchung der T&t&e. Chem& der &de, B.S., p. 365-416. RAOULTF. in A. Lacroix (1932). REYNOLDSJ. H. (1960) Rare gases in tektites. Geochim. et Co&mochim.AcEor#j, 101-114. SCENETZ~LER in A. J. Cohen (1962). SENFPLE F. E. and TIZORPE A. (195%) Magnetic susceptibility of tektites and some other glasses. Ge.o&&n.et C~G~~~. Acta 17, 234-247. SPENOE.~ L. J. (1939) Tektites and silica-glass. &f&w. &&z+ m, (107) 426-440. STAJRR. (1956) The spectral-transmissive properties of some of the tektites. Geochim. et. Coamochim. Acta 7, 43-50.
Correlation of some physical and chemical properties of moldavites
791
STARIK I. E., SOBOTOVICHE. V., SHATSM. M. and GRASHCHENROS. M. (1962) On the problem of origin of tektites. MeteoriNca XXII, 97-103. STARIK I. E., SOBOTOV~CH E. V., SRATS M. M. and LOVTSYOUSQ. P. (1961) Uranium and lead in tektites. Mete~t~~ XX, 204-207. SUESSF. E. (1914) Riickschau und Neuercs iiber die Tektitfrage. Mitt. Geol. i&s. H’ien. p. 51
121. TAYLOR S. R., SACHSM. and CHERRY R. D. (1961) Studies of tektito composition--- 1. Inwrsc relation between SiO, and the other major constituents. Oeochim. et Cosmochim. ilcta 22, 155-163. TILLEY C. E. (1922) Density, refractivity and composition rrlat~ions of some natunxl glnsws. Miner. &fog. XIX, (96) 275-294. TILTON G. R. (1958) Isotopic composition of lead from tektites. Geochim. et Chr~wh in?. d rtra 14, 323-330. VOROBIEV G. G. (1960) Study of tektite content-II. Moldavites. JUeteoritika XVIII, 36.40. WENZLICZKE A. (1880) Chemische Analyse des Bonteillenstnins von Trebitsch in Mtihwn. YeA. Nuturf. Fere. Briinn. XIX, Q-10. YASCHENKO M. L. and GERLIN~ E. K. (1953) The age and origin of tektZit,es. 7’rucl. I&. i&ol. DokembT.
Akad.
Nauk.
SSSR
2. 232-246.
Correlation of some physical and chemical properties of moldavites VLADIMIR
BOU&KA*
and PAVEL
POVONDRA~
Abstract-Relations of chemical composition, trace-element content, specific gravity, refraction and microhardness of moldavit,es, selected according to colour from several to the colour shade show that colour is a more important guide to their physical and properties than locality. Seven samples selected according to cotour from a small Dukovany (Moravia) exhibit a wide range of properties.
index of localities, chemical plot near
INTRODUCTION THE study of a large number of moldavites shows that their colour ranges from green to brown is essentially five shades: pale green, light green, bottle green, olive green and brown. One additional colour does not chromatically fit into this basic sequence-a relatively rare special “poisonous” green shade. The statistical study (FAUL and BOU~KA, oral presentation, 1963), has shown that some colours are more common in some areas than in others, but that essentially all colours can be found in most localitites. The previous opinions that colour is typical of locality are not confirmed. Brown and generally dark moldavites are not typical only of Moravia, although they clearly predominate there, but they Jso are found on the opposite end of the moldavite belt in Tgebanice, the westernmost moldavite occurrence in Bohemia, as well as in Vr&bhe, Ndchov, T$n and Vltavou and elsewhere. Green and light-coloured moldavites, on the other hand, also occur in Moravia. We have selected seven samples in the six colour shades for geochemical study. The colours were selected visually and confirmed by spe&ral measurements. The samples are listed in Table 1. Table Designation of the sample and of the eolour shade 1
2 3 4a 4b r
z Note: Muzeum,
1. Colonr scale and locality
Locality
of the samples
Colour
studied
Note
Radomilice Koroseky
pale green light green
Tir&bae PiCchov Netoliee Slavice Xetolice
bottle ._ green olive green olive green brown “poisonous” green
I
visually
fully identical
colours
Setjs of moldavite specimens arranged in this colour scale are on deposit in the N&rod& Prague and the U.S. National Museum, Washington.
* Department of Mineralogy, Geochemistry and Prague, Czechoslovakia. t Department of Analytical Chemist’ry, Czechoslovak slovakia. 783
Crys~&llo~aphy, Charles University, Academy
of Sciences, Prague,
Czecho-
VLAIXMIE
784
and PAVEL POVONDRA
&X&A
On these seven samples we have measured the density (Table a), index ot’ refraction (Table 2), light absorption (Fig. I), microhardness (Table 6), major and trace element content (spectrogra~hi~~ll~-Tables 4 and 5), and major corn~~o~l~l-lts Table 2.
W’t+ chemical annfyses of the molda,vites studiPtl
i:_%
1 Radomilice SO, TiO, Al,03 Fe,% Fe0 MgO cao N&,0 KZO
c pl.(A.Naf sp. gr.
~_ 81.52 041 7.99 0.06 1.02 1.87 1.37 2.43 3.23 99.90 1.4838 2.294
Koroseky _~._ .-__ 80.48 0~40 9.33 rt.21 I .:14 3.l.i 2.06 0.5 I 3.33 99.81 1.4875 2.317
3
4a
4b
\-r&bee --.-79.10 0.57 9.75 0.07 1.52 1.98 2.89 0.69 3.4i
n‘echov
XTstolice
81.06 0.52 9.04 @30 1.39 1.71 2.06 0.44 3.32
81.28 0.60 9.05 0.27 1.45 1.67 1.71 0.56 3‘33
99.84 1.4887 2.323
99.92 1~4852 2.322
100.04 1.4911 2.331
99.95 I*4918 2,338
99.x7 1.4966 2.370
(by wet chemical analysis-Table 2). In addition, Ing. K. Soukenik has kindly permitted us the use of chemical analyses of seven moldavites from Dukovany, Moravia, shown in Table 3. Soukenik’s samples were all found within an area of only 100 x 150 m, yet they represent the complete range of colour except for the “poisonous” green. Table 3.
SO, Al,% Fe303
Fe0 E/In0 cao MgO Na,O K&’
Quantitative chemical analyses of moldavites from Dnkovany ail collected from essentially the same spot,
_I brown
11 brown-green
111 browll-preen
IV olive-green
V green
75.0.!? 13.74 0.09 3.2s 0.11 2.29 1.55 o-50 3.13
75.90 12.09 0.26 2.41 0.09 2.69 1.95
75.72 13.14 0.18 2.7r,
76.78 12.00 0,57 2.30 0.13 1.49 1.58 0.80 3.66
77.60 ll*Ob 0.46 2.16 0.07 2.55 1.85 1.08 2.83
99.74
99‘38
99.31
99-54
0.89 3~50
0.09 2.12 1.62 0.73 3‘42 --..-_-_99.77
(Moravia).
\‘I green
-.
VII light, preen
77~52 10.92 0.72
80.10 10.03 0.70
I.75 0.07 2.72
0.04 2.20
I*60 0.78 3.42
1.38 u.75 3.X)
1,a:!
99.82
RESULTS
All samples were tested for uranium oontent by luminescence analysis. The sensitivity of the method is 0-z ppm and all but two samples gave negative results in three ohecks. Only the samples from Net&ice showed a trace. Light-absorption curves, measured on plates 2 znm thick in the visual spectrum are shown in Fig. 1. The shape of the curves is characteristic of glasses except for a higher absorption in the red end (right side). According to COHEN (195&j, the
Spectrograph
Radomilicc 1 Koroseky 2 Vr&bae 3 N&hov 4a Sotolice Ib Slavice 5 Xetolice 8
Locality and No.
Spectrograph
KSA 1.
0.0056 0.0084 0.0094 0~0090 0.0074 0.0074 woo.i7
Rb%
Al, Fe, Mg, Ca, K -41, K, Mg Fe, Ca
Al, Fe, Ca, Mg, K Al, Fe, Ca, Mg, K Al, Ca, Mg, Fe, K
sa
Sa
_ Xa
Na
N&
Ti Mn Ti
Ti
Ti Mn Ti Mn Mn
Ti, Ca, Mn, Na Na Ti Mn
Al, Mg, K, Fe
Al, Ca, Mg, Fe, K
l--O.1 y0
> 1e/e
Ba 31n
Ba
Ba
Ba, Pb, Zn Ba
Ba
O.l-0.01%
V, Ue Sr, V, Sr, V, Ni, Zn, Xi, Cu,
B, Cu, Zn, Cr,
0.0028 0.0026 0.0026 -: 0.001 -:a~001 *: o*oo 1
0~0019
CS%
pb% 10.001
Ga%
n.on1
CU%
i 0~001 < 0.001 .; 0+01 tWX11 -:O.OOl -r-o~oOl -. owl
Ag%
0.01
zn %
0~005?.l.
0.0029 0.0030 0.0025 0.0024 0+)028 0.0017
0%
0.0020 0.0020 0*0019 0.0019 0~0020 0.0018 0.0023
Ni 0%
Co, Ag Pb Ag, B, Co
__
MO %
studied
Ga, Cr, Sn, Pb,
Xi, B, Ga, Co,
0.0021 0.0024 ct~OOZ*~ 0.002,5 W002d 0.0028 0,002,i
I7 %
Li Be, Y Ga, Y Be, Li
Pb
Co%
Sr, Pb, Th, Co, Mo, Li Pb, Y Li
V, Ni, B, Ag, Be, Cu, Ga, Co, Cr, Ba Sr, Cu, B, Zn, Ag, V, Ni, Cr, Ga, Co, Be Sr, Cu, B, Ag, Co, V, Ni, Ga, Be Sr, Cu, B, Zn, Ag, V, Ni, Cr, Ga, Co, Be Sr, Cr, Cu, Zn, A,g, Rb Li, Y Li Pb, Y Li, Y
?
to.01 y*
analyses of moldavites (optical spectrograph)
Table 5. ~uax~tit~~ti~,e sp~~t~ograph~c analyses of some trace elements in the moldavites
Zeiss Q 24.
Xi
Si
SIavice
6
Si
Netohce 4b
Netolioe
Si
Ngchov 4a
5
Si
VrabFe 3
Si
Si
1
> 10%
Koroseky 2
Radomilice
Lot. and No.
Table 4. Semi-quantitative
786
VLADIMIR
BOUSKA and PAVEL POVONDHA
Table 6. Microhardness of the moldavites, measured by apparatus according to HANANIAN, model 13 32, and special objective Apochromat 0.95 (Zeiss, Jena) Hm Locality Slavice K&hov Hlavice Koroseky Radomilice
(lolor r, 6 4 2 1
(g/P2) 916 1001 1099 1211 -1211
colour of tektites is primarily due to absorption by iron, trivalent in the violet end and bivalent in the red end. The moldavite from Radomilice (No. 1) is pale green and has a low content of iron. Its curve also shows only a slight rise toward the red and almost none toward the violet end.
Fig.
1.
Light
absorption of 2 mm plates cut from the specimens Table l), plotted as a function of wavelength.
studied
(see
STAIR (1955) writes that the colour could be caused by combined absorption by iron, nickel, chromium and manganese oxides. In our samples, trivalent iron is present only in subordinate quantities, compared to FeO. Therefore, to express colour as a function of iron content better, we recalculated the iron contents to ferrous oxide (Fig. 2). Except for the “poisonous” green sample (No. 6, N&lice), we obtain a close relation between colouring and iron content. Also remarkable is the agreement in recalculated iron content of samples 4a and 4b (NGchov and Nettilicte) both of which are of the same colour (olive green) but come from looalities 40 km distant from each other. The “poisonous” green sample from Netolice (No. 6) shows a steep rise in absorption toward the red end but shows relatively low iron contents. Its behaviour is Apart from the slightly higher anomalous with respect to the entire sequence. content of nickel, there is no other fact to explain its intense green oolour.
Correlation of some physical and chemical properties of moldavites
787
% 2
1
ZFe 0 Fe 0 I .
i
0
-_----1 L-
Fe203
____.
f
2
3
4b
4%
d
6
Fig. 2. Bivalent and trivalent iron content (solid lines) and summary iron content expressed as Fe0 (da,shed line), of moldavites studied, plot&d as a function of colour shade.
Perhaps the high content of alkaline earths and the deficiency in potassium could have combined to enhance the influence of colouring agents present in small amounts. The moldavites from Dukovany analysed by Soukenik (Fig. 3) show the same relation between Fe0 and colour, but his colour scale differs slightly from ours. The silica content in his sample clearly falls with increasing iron content. Molu’avifes -Dukovany
1
2
3
4
5
6
7
Fig. 5. Silica and iron contents of moldavites collected from a 100 x 150 m plot near Dukovany (Moravia), plotted as a function of their colour shade, after Soukenik. Note that Soukenik’s colour scale has seven steps from green to brown and does not include the “poisonous” green. The absorption curves of our samples also show slight irregularities in the This phenomenon is unexplained for the vicinity of 500 and 640 m,u wavelengths. time being. Relation of indices df refraction to densities confirm the seatements of JE~EK and WOLD&KX (1910), TILLEY (1922), PREUSS (1935) and SPENCER (1939) that the
\jLADEMilt ~OU&CA and PAvEL
788
POVONDRA
index of refraction of moldavites i8 an approximately linear fu~ctiol~ of density, as shown in Fig. 4 which includes all presently available data. !lTheindex a,nd den&y are roughly determined by the summary content of alkaline earths and iron.
Fig. 4.
Index of refraction VS. specific gravity of moIdavites. available data are shown.
All presently
% 4.
CC0
2’
a
iii& . Fe, 4 6
.W
40 46 5 1 2 3 Fig. 5. Chemical composition of the moldavites stndied vs. their colour sha,dr.
On Mohs’ scale, the hardness of moldavites falls between 6.5 and 7. Moldavites being essentially silica glass with 20-25 % of other oxides added, it would be expected that those higher in silica also would be harder. MoldaviteN with the higher silica contents are usually lighter in oolour so that one may compare the hardness of moldavites with their oolour (Table 6). The sample from Radomilice (No. 1) showed a variation in microhardness and the average value is reported. No such variation was observed in the other sample. Table 7. Specific gravity, index of refraction, iron content (expressed as FeO), and stunmary content of alkaline earths and iron of the samples studied SP. gr.
n@ h‘a)
ZF&
2.294 2.317 2.322 2.323 2.331 2.332 2-370
1.4838 1.4875 1.4862 1.4887 1.4911 l-4918 l-4956
1.074 1.53 1.69 1.66 1.58 2.08 l-31
ZFeO, MgO, CaO 4.314 5.74 5.07 5-43 6.45 4.83 7-86
NO.
1 2 4b 4a 3 5 6
Correlation of some physical and chemical properties of moldavites
789
The major-component contents (except for silica) are given in Fig. 5. It shows that TiO and K,O are essentially constant over the entire colour range and the remaining components vary only slightly in the green-brown sequence. Marked irregularities appear in sample No. 6, the “poisonous” green one. It is understandable that variations in the content of the alkaline earths would be reFigure 6 shows the almost mirrored flected in changes in the alumina content. courses of the sums MgO + CaO + Na,O + K,O and TiO, + Al,O,, manifesting the mutual influence of acid and basic components.
f-l
_I-:---:-: dl
6
O+CaO
f f a#+&0 zTiO2 +A/20J
ro.i 9
7 6
Fig. 6.
i
2
3
40
4b
5
6
Siunmary content of alkalis plus alkaline earths and alumina plus t,itania, plotted against colour shade.
Our results do not quite support COHEN’S (1962) conclusion that silica content of moldavites tends to decrease from west to east. Soukenik’s analyses of the Dukovany moldavites, all essentially from the same spot, still show a wide variation in silica content (Fig. 3). Acknowledgements-We are indebted to 1)r. Z. SULCEK of the Central Geological Survey in Prague for the use of light absorption apparat(us and to B. RYBAKOVA and M. MIKSOVSK+ for making the spect,ral analyses. We thank A. BL~~ML of the Rudne doly, Pfibram, for the microhardness measurements and INC. K. SOUDEN~K of Pierov for the use of his analyses of the Dukovany moldavites. Prof. H. FATTLassisted in the preparation of the English manuscript. REFERENCES BARNES V. E. (1940) North American Tektites, pp. 477-656. University of Texas Publications 3945. JJECK R. (1910) Uber die in Tektiten eingeschlossenen Gase. Mber. Dt.sch. Geol. Ges. LX II 240-245. BRUN A. in R. Beck (1910). COHEN A. J. (1958) The absorption spectra of tektites and other natural glasses. Geochim. et Cosmochim. Acta 14, 279-286. COHEN A. J. (1959) Moldavites and similar tektites from Georgia, U.S.A. Geochim. et Cosmochim. Acta 17, 150-153. COHEN A. J. (1960a) Trace element relationships and terrestrial origin of tektites. Nature, Lond. 188, 653-654. COHEN A. J. (1960b) Germanium content of tektites and other natural glasses. Implications Report of the Twenty-First Session of the International concerning the origin of tektites. Geological Congress, Norden, Vol. l., pp. 30-39. Berlingske Bogtrykkeri, Copenhagen. COHEN A. J. (1962) Asteroidor Comet-Impact Hypothesis of Tektite Origin I. The Moldavite Strewn-Fields and the Niirdlinger Ries (Ries Kessel) Crater. Mellon Institute, Pittsburgh, Pennsylvania.
790
VLADIMIR
BOUSRA
and PAVEL PO~ONDRA
DUBEY S. V. in J. Oswald (1942). DVO~SEPI?. (1883$ Die am Iglawaflusse abgesetzten Moldavit-Quarzgeralle. Programm tirs Gymnasiums in Trebitsch, pp. 2-17. EE~~ANNW. D. (1960) Nickel in tektites by activation analysis. ~eoc~~~. et ~~~$?~z,oc~:~~t~,. ._I ~trr
19,14S-156. EH~N
W. D. and KOHMANT. P. (1968) Cosmic-ray-induced radioactivities in mrteoritcs 11:
AlaB, BeXo and Coao in aexolites, siderites and tektites. Geochim. et Cosnaochim. Arta 14, 364-379. ERDMANNL. 0. (1832) Jahrbuoh fur technische und okonomiecheChemie. Leipzig. FRIED-N I. (1958) The water, deuterium, gas and uranium content of tektites. &o&m. t‘t C~c~~~. Acta 14, 316-322. GENTNERW., LIPPOLT H. J. and SCHAEFFER 0. A. (1963) Argo~b~timm~g of Kaliumminewlien XI: Die Kalium-Argon-Alter des Gliiserdes Nordlinger Rieses und der bohmisch-mahrischen Tektite , Geochim. et Cosmochim. A& 87, 191-200; also A. J. Cohen (1962). H~BERMANNJ. in F. Dvorsk$ (1883). HANAMANNJ. (1893) 0 povaze Eeskeho vltavinn. Casopis pro prfimsyl chemickJi. C. I I.. rok III., p. 365-366. HAUERV. K. (1854) in Arbeiten in dem chemisehenLabora~rium der k. k. geologi~hen Reichsanstalt. J. 6. GeoE.Be&&son&.(~~~~u~~) Wie% 4, (VII} 868-869. JEZEK B. and WOLD~ICH J. (1910) P?isp&vek k IeSeni otazky tektitove. Rozpravy Eeske akademie, roe. XIX., tf. II., E. 30. JOHNv. C. (1880) in K. v. Hauer (1880) Bouteillensteinvon Trebitsch. l’erh. &ol. Reirhsl An& (StAnst) Wien 16, 282-284. JOHN v. C. (1889) Ueber den Moldavit oder Bou~ille~tein von Radomilic in Biihmen. J. 0. til. Redbait ~R~~~~~t) Widen Z3@,473-476. JOHNv. C. (1899) Ueber die ohemischeZusammensetzungder Moldavite. t’erh. GeoE.ReiehsAn& (St&&) Wien 6,7, 179-182. JOENSENA. (1906) Beitriigezur Kenntisn natiirlicherund ktinstlicherGliiser. ii’ck. Phys.-f&t~. GM. Kon@~&. XNII, (II) 105-110. KLAPPRO~~M. (1816) Beitriige zur chemisehen Kenntnis der Minearlien. &faguz. d. #es. d. No&m. ~~e~~. Bert& (1795-1815). XZINOV E. L. (1958) Some co~ider~~o~ on tektites. Geoohim. et ~o~~~rn. AC& 14,25S-266. Lac~onr A. (1932) Les Tectites de I’Indochine. Arch. Mw. Nat. Hi&. 6, Serie T. VIII. 193-236. LUDWIUE. (1910) in F. E. Suess (1914). M&sONB. H. (1959) Chemical oomposition of tektites. Nature, Lond. 199,254-255. &%ALYouGA D. P. (1949) The cognition of the nature of tektites. Meleoritilca6, 92-100. NOV&?EKR. (1932) Chemicky a fyzik&lni tizkum n&ktejrch vltavinfi eeskych a moravsk&h. Rozpravy II. tf. Ceske akademie, roe. XLTI., C. 31. OSWALDJ. (1942) Meteorioke &lo. N&l. 6esk4 akad. v&d. a um&ni. Praha. PANETRF.,PETE~EN K. W. und CHLOUPEK J. (1929) Uber den Helium-Gehalt von “Moldaviten“ und ki.instliehenGl&sern. VI, Mitt&l. Ber. Citem. Ges. 68, 801-809. PINSONW. H. JR., HERZO~L. F., FAIRBA~RN H. W. and CORMTE~ R. F. (1958) Sr/Rb age study of tektites. Geochim. et Coemochim. Acta 14, 331-339. PZEIS K. in J. Oswald (1942). P~EUSSE. (1934) Chrom und Nickel in Tektiten. N~~~~8s~~~~n @, 480. PREUSS E. (1938) ~pekt~~nal~~he Untersuchung der T&t&e. Chem& der &de, B.S., p. 365-416. RAOULTF. in A. Lacroix (1932). REYNOLDSJ. H. (1960) Rare gases in tektites. Geochim. et Co&mochim.AcEor#j, 101-114. SCENETZ~LER in A. J. Cohen (1962). SENFPLE F. E. and TIZORPE A. (195%) Magnetic susceptibility of tektites and some other glasses. Ge.o&&n.et C~G~~~. Acta 17, 234-247. SPENOE.~ L. J. (1939) Tektites and silica-glass. &f&w. &&z+ m, (107) 426-440. STAJRR. (1956) The spectral-transmissive properties of some of the tektites. Geochim. et. Coamochim. Acta 7, 43-50.
Correlation of some physical and chemical properties of moldavites
791
STARIK I. E., SOBOTOVICHE. V., SHATSM. M. and GRASHCHENROS. M. (1962) On the problem of origin of tektites. MeteoriNca XXII, 97-103. STARIK I. E., SOBOTOV~CH E. V., SRATS M. M. and LOVTSYOUSQ. P. (1961) Uranium and lead in tektites. Mete~t~~ XX, 204-207. SUESSF. E. (1914) Riickschau und Neuercs iiber die Tektitfrage. Mitt. Geol. i&s. H’ien. p. 51
121. TAYLOR S. R., SACHSM. and CHERRY R. D. (1961) Studies of tektito composition--- 1. Inwrsc relation between SiO, and the other major constituents. Oeochim. et Cosmochim. ilcta 22, 155-163. TILLEY C. E. (1922) Density, refractivity and composition rrlat~ions of some natunxl glnsws. Miner. &fog. XIX, (96) 275-294. TILTON G. R. (1958) Isotopic composition of lead from tektites. Geochim. et Chr~wh in?. d rtra 14, 323-330. VOROBIEV G. G. (1960) Study of tektite content-II. Moldavites. JUeteoritika XVIII, 36.40. WENZLICZKE A. (1880) Chemische Analyse des Bonteillenstnins von Trebitsch in Mtihwn. YeA. Nuturf. Fere. Briinn. XIX, Q-10. YASCHENKO M. L. and GERLIN~ E. K. (1953) The age and origin of tektZit,es. 7’rucl. I&. i&ol. DokembT.
Akad.
Nauk.
SSSR
2. 232-246.