Crystals
Blue tiger eye
Falcon’s Eye • Hawk’s Eye • Blue Tiger’s Eye — blue chatoyant quartz with aligned amphibole fibers Principal host: polycrystalline quartz, SiO2 Blue component: comparatively unoxidized riebeckite–crocidolite fibers Optical signature:...
Blue tiger eye
Falcon’s Eye • Hawk’s Eye • Blue Tiger’s Eye — blue chatoyant quartz with aligned amphibole fibers Principal host: polycrystalline quartz, SiO2 Blue component: comparatively unoxidized riebeckite–crocidolite fibers Optical signature:...
Black onyx
Black onyx • straight-banded chalcedony, composed chiefly of microcrystalline quartz with moganite Composition: SiO2 Signature architecture: parallel black, gray, white, or blue-white layers Mohs 6.5–7 • specific gravity about 2.58–2.64...
Black onyx
Black onyx • straight-banded chalcedony, composed chiefly of microcrystalline quartz with moganite Composition: SiO2 Signature architecture: parallel black, gray, white, or blue-white layers Mohs 6.5–7 • specific gravity about 2.58–2.64...
Anthophyllite
Anthophyllite • orthorhombic magnesium–iron amphibole Idealized composition: Mg7Si8O22(OH)2 Iron-rich relative: ferro-anthophyllite Al-rich compositions grade toward gedrite-related amphiboles Cleavage: approximately 56° and 124° Mohs 5.5–6 • specific gravity commonly 2.85–3.2 Habit:...
Anthophyllite
Anthophyllite • orthorhombic magnesium–iron amphibole Idealized composition: Mg7Si8O22(OH)2 Iron-rich relative: ferro-anthophyllite Al-rich compositions grade toward gedrite-related amphiboles Cleavage: approximately 56° and 124° Mohs 5.5–6 • specific gravity commonly 2.85–3.2 Habit:...
Ametrine
Ametrine • natural or synthetic bicolor quartz containing amethyst and citrine-colored sectors Composition: SiO2 with iron-related color centers Colors: violet to purple and yellow to golden orange Crystal system: trigonal...
Ametrine
Ametrine • natural or synthetic bicolor quartz containing amethyst and citrine-colored sectors Composition: SiO2 with iron-related color centers Colors: violet to purple and yellow to golden orange Crystal system: trigonal...
Zoisite
Zoisite · orthorhombic calcium-aluminum sorosilicate and polymorph of clinozoisite Ca₂Al₃(SiO₄)(Si₂O₇)O(OH) IMA symbol · Zo Tanzanite · blue-to-violet, vanadium-bearing gem zoisite Thulite · pink manganese-bearing zoisite Anyolite · ruby-bearing green zoisite...
Zoisite
Zoisite · orthorhombic calcium-aluminum sorosilicate and polymorph of clinozoisite Ca₂Al₃(SiO₄)(Si₂O₇)O(OH) IMA symbol · Zo Tanzanite · blue-to-violet, vanadium-bearing gem zoisite Thulite · pink manganese-bearing zoisite Anyolite · ruby-bearing green zoisite...
