Prasiolite (from Greek: πράσιος “light green”,letters. “ Leek color” + λίθος “stone”) - a variety of quartz , a flint mineral of green color (other names are green quartz or vermarine) [1] . Transparent, the color of onion-green, the saturation of the shade can vary from pale gray-green to deep grassy green. [1] (Not to be confused with prazem !).
| Praziolite | |
|---|---|
 | |
| Formula | SiO 2 |
| Physical properties | |
| Colour | Onion green |
| Trait color | White |
| Transparency | Transparent or translucent |
| Hardness | 7 |
| Cleavage | Missing |
| Kink | Crusty, very fragile |
| Density | 2.65 g / cm³ |
| Syngonia | Trigonal |
| Refractive index | 1,544 - 1, 553 |
Content
Application
Mainly used for jewelry. Often as an imitation of more expensive gems. Outwardly resembles beryl , peridot , tourmaline .
Deposits
Meets with amethyst. It was discovered in metamorphic , igneous and volcanic rocks. [1] Reported findings of natural praziolite in Brazil , Canada ( Thunder Bay ) [2] , Namibia , Poland , Tanzania , USA ( New Hampshire , Nevada ), Zambia [1] .
Processing
It is rare in nature, today most of the praziolite on the market is the products of heating and radiation of amethyst. [1] . The green tint of crystals obtained by heating can fade with prolonged exposure to sunlight [3] .
Since 1950, it has been obtained by calcining at 500 ° C amethyst and yellowish varieties of quartz from the Brazilian Moktesum deposit or the state of Arizona (USA).
Natural prasiolite has a light green hue, saturated, dark green color of the crystals, most likely, indicates heat treatment [4] .
Notes
- ↑ 1 2 3 4 The Quartz Page: Prasiolite Neopr . www.quartzpage.de. Date of appeal September 17, 2018.
- ↑ Power Systems Advanced Research . - Office of Scientific and Technical Information (OSTI), 2007-03-31.
- ↑ Lazzarelli, Giulio . - Oxford University Press, 2011-10-31. - (Benezit Dictionary of Artists).
- ↑ Grande, Lance. Gems and gemstones: timeless natural beauty of the mineral world . - Chicago: University of Chicago Press, 2009 .-- 369 pages p. - ISBN 9780226305110 , 0226305112.
Literature
- prof. Schumann B. (Walter Schumann). The world of stone. In two books. Book 2. Precious and ornamental stones / trans. with him. Cand. geol.-mineral. Sciences T. B. Zdorik and Ph.D. geol.-mineral. Sciences G. Feldman. - M .: Mir , 1986 .-- S. 114 .-- 264 p.