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The most significant source of uvarovite historically has been a now-closed copper mine at Outokumpu, Finland, from where most museum specimens have been collected. [7] The uvarovite crystals found in the Outokumpu district are among a wide range of chromium-rich silicate phases found in association with volcanogenic copper-cobalt-zinc sulfide ore deposits which are known to have an unusually ...
Calaverite occurs as monoclinic crystals, which do not possess cleavage planes. It has a specific gravity of 9.35 and a hardness of 2.5. Calaverite can be dissolved in concentrated sulfuric acid. In hot sulfuric acid the mineral dissolves, leaving a spongy mass of gold in a red solution of tellurium.
Clear and well-colored stones are rare as the radioactivity tends to degrade the crystal matrix over time in a process known as metamictization. The type locality is Eheliyagoda , Ratnapura District , Sabaragamuwa Province , Sri Lanka , [ 2 ] where it was first described in 1955 by F. L. D. Ekanayake, a Sri Lankan scientist, [ 5 ] [ 6 ] and it ...
Charoite (/ tʃ æ r oʊ. aɪ t / CHAR-ow-ait) is a rare silicate mineral with the chemical composition K(Ca,Na) 2 Si 4 O 10 (OH,F)•H 2 O, first described in 1978.It is named after the Chara River, despite its being 70 kilometres (43 mi) away from the discovery place.
The word prasiolite literally means "scallion green-colored stone" and is derived from Greek πράσον prason meaning "leek" and λίθος lithos meaning "stone". The mineral was given its name due to its green-colored appearance. Natural prasiolite is a very light, translucent green. Darker green quartz is generally the result of ...
Langbeinite is a potassium magnesium sulfate mineral with the chemical formula K 2 Mg 2 (SO 4) 3. Langbeinite crystallizes in the isometric -tetartoidal (cubic) system as transparent colorless or white with pale tints of yellow to green and violet crystalline masses.
It is orange-red in color, melts at 320 °C, and burns with a bluish flame releasing fumes of arsenic and sulfur. Realgar is soft with a Mohs hardness of 1.5 to 2 and has a specific gravity of 3.5. Its streak is orange colored. It is trimorphous with pararealgar and bonazziite. [2]
It is translucent and brownish-yellow and has an index of refraction of 2.40–2.41 and a specific gravity of 3.2–3.3 . Its hardness is theoretically superior to that of cubic diamond (up to 58% more), according to computational simulations, but natural specimens exhibited somewhat lower hardness through a large range of values (from 7–8 on ...