|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
|
MD-179860 - Fayalite, Cristobalite - - Archived Little Lake Perlite deposits (Desert Materials Corp. deposit), Little Lake area, Coso Hot Springs, Coso District (New Coso District), Inyo Co., California, USA small cabinet, 6 x 4.9 x 4.1 cm.
6 x 4.9 x 4.1 cm. Lithophysae in obsidian is the matrix for an open "egg" of light gray, cristobalite ( a tetragonal polymorph of quartz) which lines the inside. Perched inside the cristobalite vug is a gemmy, yellow-green crystal, 0.2 cm across, of fayalite. Ex. Martin Zinn Collection.
MD-217451 - Cristobalite, Fayalite - - Archived Canyon Butte occurrence (Couger Butte), Canyon Butte, Siskiyou Co., California, USA small cabinet, 6.2 x 6.2 x 3.6 cm.
6.2 x 6.2 x 3.6 cm. A fine specimen featuring "eyes" of high-temperature cristobalite scattered in highly lustrous, jet-black obsidian from an uncommon California locale - Couger Butte, Siskiyou County. Some of the "eyes" have faint hints of gemmy, micro-blades of fayalite, an olivine group mineral. Obsidian (volcanic glass) cools too quickly, to crystallize. Thus, it is unusual to see minerals attached. The "eyes" or spheres of high temperature cristobalite (SiO2) are actually the result of devitrification, or loss of silica from the obsidian. Ex. Mullane Collection.
MD-237494 - Cristobalite, Fayalite - - Archived Canyon Butte occurrence (Couger Butte), Canyon Butte, Siskiyou Co., California, USA cabinet, 13.4 x 9.9 x 6.2 cm.
13.4 x 9.9 x 6.2 cm. A visual and fine cabinet specimen of "eyes" of high-temperature cristobalite scattered in highly lustrous, jet-black obsidian from an uncommon California locale - Cougar Butte, Siskiyou County. Some of the "eyes" have faint hints of gemmy, micro-blades of fayalite, an olivine group mineral. Obsidian (volcanic glass) cools too quickly, to crystallize. Thus, it is unusual to see minerals attached. The "eyes" or spheres of high temperature cristobalite (SiO2) are actually the result of devitrification, or loss of silica from the obsidian. Certainly, a most unusual and uncommon specimen. Ex. Mullane Collection.
MD-254004 - Cristobalite, Fayalite, Obsidian - - Archived Canyon Butte occurrence (Couger Butte), Canyon Butte, Siskiyou Co., California, USA small cabinet, 5.8 x 5.8 x 4.4 cm.
5.8 x 5.8 x 4.4 cm. A visual and showy specimen of a 2.5 cm "eye" of high-temperature cristobalite nicely set in highly lustrous, jet-black obsidian from an uncommon California locale - the Couger Butte, Siskiyou County. The "eye" has three clusters of gemmy, olive-green, micro-blades of fayalite, an olivine group mineral. Obsidian (volcanic glass) cools too quickly to crystallize. Thus, it is unusual to see minerals attached. The "eyes" or spheres of high temperature cristobalite (SiO2) are actually the result of devitrification, or loss of silica from the obsidian.
MD-39952 - Cristobalite, Fayalite - - Archived Siskiyou Co., California, USA cabinet, 11.8 x 8.5 x 6.8 cm
This example of cristobalite on obsidian, created by devitrification of the obsidian, exhibits a large vesicle 3 cm across. SHOWY! 11.8 x 8.5 x 6.8 cm
MD-40048 - Cristobalite, Fayalite - - Archived Canyon Butte occurrence (Couger Butte), Canyon Butte, Siskiyou Co., California, USA small cabinet, 5.9 x 3.8 x 3.8 cm
Obsidian(volcanic glass) cools too quickly, to crystallize. Thus, it is unusual to see minerals attached. The spheres of high temperature cristobalite(SiO2) are actually the result of devitrification, or loss of silica from the obsidian. Most unusual. 5.9 x 3.8 x 3.8 cm
MD-40050 - Cristobalite, Fayalite - - Archived Canyon Butte occurrence (Couger Butte), Canyon Butte, Siskiyou Co., California, USA thumbnail, 2.5 cm
This example of cristobalite on obsidian, created by devitrification of the obsidian, exhibits a large vesicle 2.5 cm across. 6 x 5.4 x 2.5 cm
MRZ329 - Fayalite on Cristobalite - $ 250 SOLD Little Lake, California, USA small cabinet, 6 x 4.9 x 4.1 cm ex. Martin Zinn
Amygdaloidal obsidian is the matrix for an open "egg" of light gray, cristobalite ( a tetragonal polymorph of quartz) which lines the inside. Perched aesthetically inside the cristobalite vug is a gemmy, yellow-green crystal, 0.2 cm across, of fayalite. This is an end member of the olivine group, of which, the most famous member is forsterite var. peridot. But you even more seldom see nice sharp (gemmy!) fayalites. All Content and Design ©1996-2010 The ArkenstonePowered by http://mineralwebsites.comBy-species Galleries | ||||||||||||||||||
