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25/03/2008:
Articles: Chemical Composition of Sawdust from Lunar Rock 12013 and Comparison of a Java Tektite with the Rock

From: D. L. Showalter, H. Wakita, R. H. Smith, R. A. Schmitt, D. E. Gillum, and W. D. Ehmann .

Department of Chemistry and Radiation Center, Oregon State University, Corvallis 97331 Department of Chemistry, University of Kentucky, Lexington 40506

Abundances of 11 major and minor elements and 11 trace elements have been determined by instrumental neutron activation analysis of two Apollo 12013 rock fragments, a sample of rock 12013,17 sawdust, and a Java tektite (J2).
Although the abundances of major elements in tektite J2 are similar to those of rock 12013, comparison of the minor and trace elements shows that no fragment or sawdust of rock 12013 that has been analyzed to date is chemically similar to tektite glass.
Rock sawdust is representative of "whole rock" composition only if the amount of contamination from the sawing process is known.
After appropriate correction for saw wire contamination, analyses of sawdust yield fairly accurate averaged elemental compositions of complex clastic lunar and other rocks.

   
25/03/2008:
Lake Toba, Sumatra, INDONESIA and the Origin of Tektites: S. R. TAYLOR Department of Geophysics and Geochemistry, Australian National University, Canberra 2600, Australia.

KAYSING suggested recently1 that Lake Toba, Sumatra, Indonesia, was a possible source area for the Australian group of tektites.
This suggestion was based on extrapolation from the observation of McColl and Williams2 that the "majority of australite localities in south central Australia are concentrated along a line extending northwestwards ....
A second subparallel line may exist in the west of South Australia, separated from the main line by an extensive tract of australite-deficient country".
They consider that these lines represent primary distribution patterns, and Kaysing1 suggests that suitable assumptions about ejection angles and allowance for the Earth's rotation "brings the intersection of the infall lines to Lake Toba".


16/02/2008
 TEKTITE of the month: 		   

 

  

21/02/2008
Notes on Bellitonites:
Synonyms : Agni-mani, pearl of fire. Very rare, collector's stone.
The stones are only remarkable for their form, resembling to buttons with an irregular rim, the surface pitted like moldavites.

" Agni-mani ", also called Agni gemma, is one the rarest stones. Modern science calls it tektite and billitonite is a variety.

A particular attractive stone: black with dark green reflections on the sides, very irregular surface, covered with small craters.

Because of its rarity, the stone is considered by the local people to be a magical stone with beneficial powers.

On Java and Borneo, and in Tibet, people ascribe a protective power to tektites. The local people that found a tektite, buried it, believing that it favoured the growth of the mineral.

Tektites were also discovered in Oceania, Indo-China, Colombia and Peru.
The mineralogist G. Guillemin found that tektites are meteorites formed of a transparent glass, dark blue, green, rarely brown, very rich in SiO2 (± 70%), rich in Al2O3 (10 to 16%), Fe and Mg, but poor in alkalis and lacking any water.

They owe their characteristic form and aspect of their surface (crossed striae) to their flight trough the atmosphere.

Bellitonite Properties:
: - Colour: black.
- Transparency: translucent to opaque
- Hardness: 5.5
- S.G: 2.36 to 2.51
- R.I: 1.
49 to 1.53

02/2008
Notes on Tektites from Wikipedia:
Tektites (from Greek tektos, molten) are natural glass objects, up to a few centimeters in size, which - according to most scientists - have been formed by the impact of large meteorites on Earth's surface.
Tektites are among the "driest" rocks, with an average water content of 0.005%. This is very unusual, as most if not all of the craters where tektites may have formed were underwater before impact.
Also, partially melted zircons have been discovered inside a handful of tektites.
This, along with the water content, suggests that the tektites were formed under phenomenal temperature and pressure not normally found on the surface of the Earth.
http://en.wikipedia.org/wiki/Tektite t