Tasmanite (mineral)
| Tasmanite | |
|---|---|
| General | |
| Category | Fossil resins |
| Formula (repeating unit) | C40H12402S |
| Identification | |
| Color | reddish brown to brown |
| Crystal habit | narrow scaly lenses, difficult to separate from the main rock |
| Cleavage | absent |
| Fracture | conchoidal, viscous |
| Tenacity | viscous, soft mineral |
| Mohs scale hardness | ~ 2 |
| Luster | waxy, greasy |
| Streak | white |
| Diaphaneity | translucent |
| Density | ~ 1,8 |
Tasmanite, or Tasmanian amber (in the original sense of the word: “discovered in Tasmania”) — a rare regional mineraloid, a brownish-reddish fossilized organic resin from the island of Tasmania, formed in some deposits of the parent rock (tasmanite shale) and known by the same name: tasmanite.[1]: 376
Found in bituminized shales on the banks of the Mersey River (northern Tasmania), this mineral was examined and described in 1865 by Professor A. J. Church.[2] Meanwhile, translucent tasmanite is not formed everywhere where there are deposits of the sedimentary rock of the same name, but only in some layers.
Over the next century and a half, almost no new evidence appeared about Tasmanian amber.
Origin and genesis
The parent rock, also called Tasmanite, is itself a special type of sedimentary rock of organic origin, common not only in Tasmania or Australia, but also throughout the globe. Tasmanite as a rock is a typical oil shale, liptobiolite-sapropelite with a very high carbon content, formed from Late Permian and Carboniferous deposits of unicellular algae. In appearance, Tasmanite is a fossilized amorphous mass containing large quantities of remains of spores (cysts) and pollen. In its pure form, tasmanite consists almost entirely of flattened and compressed microspore shells. The initial forming substance is necroma of brackish-water seaweeds from the genus Tasmanites (Latin: Tasmanites; Newton, 1875).[3] The color of the differences is always dark, mixed, the tonality varies depending on the location in the range from gray-brown to black; Due to the high spore content, most samples appear to be covered in yellow pollen. The same picture is visible on the tasmanite fracture.[4]: 151
References
- ^ F. Yu. Levinson-Lessing. Petrographic Dictionary. — Leningrad-Moscow: State Scientific and Technical Geological and Petroleum Publishing House, 1932. — 462 p.
- ^ Сhurch N. J., The latest research into the landscape of Northern Tasmania and its natural minerals. — 1865, р. 480.
- ^ Peters, K.E. and Moldowan, J.M. Effects of Source, Thermal Maturity, and Biodegradation on the Distribution and Isomerization of Homohopanes in Petroleum. Organic Geochemistry, 17, 47-51 (1991).
- ^ Brod I. O. Fundamentals of oil and gas geology. Textbook for universities and oil universities. 2nd ed., rev. and additional Section: “origin of liptobiolites and sulfur”. — Moscow: Publishing house Moscow University, 1953. — 339 p.