Crystals
Citrine
Quartz family Yellow to orange quartz SiO2 Mohs 7 Trigonal crystal system Citrine: Golden Quartz of Warmth, Clarity, and Radiant Structure Citrine is the yellow-to-orange variety of quartz, valued for...
Citrine
Quartz family Yellow to orange quartz SiO2 Mohs 7 Trigonal crystal system Citrine: Golden Quartz of Warmth, Clarity, and Radiant Structure Citrine is the yellow-to-orange variety of quartz, valued for...
Aquamarine
Blue to blue-green beryl Be3Al2Si6O18 Hexagonal crystal system Mohs 7.5–8 Iron-colored silicate March birthstone Aquamarine: Sea-Blue Beryl, Hexagonal Light, and the Clarity of Pegmatite Crystals Aquamarine is the blue to...
Aquamarine
Blue to blue-green beryl Be3Al2Si6O18 Hexagonal crystal system Mohs 7.5–8 Iron-colored silicate March birthstone Aquamarine: Sea-Blue Beryl, Hexagonal Light, and the Clarity of Pegmatite Crystals Aquamarine is the blue to...
Fossil
Body, trace, microfossil, and chemical evidence Taphonomy and deep time Most common in sedimentary rock Mineral replacement, impressions, and original material Fossils: How Life Becomes Evidence and Deep Time Becomes...
Fossil
Body, trace, microfossil, and chemical evidence Taphonomy and deep time Most common in sedimentary rock Mineral replacement, impressions, and original material Fossils: How Life Becomes Evidence and Deep Time Becomes...
K2
Azurite-bearing granitic rock Quartz, feldspars, and mica Azurite: Cu3(CO3)2(OH)2 Malachite: Cu2CO3(OH)2 Composite hardness: approximately 3.5–7 Khaplu area, Gilgit-Baltistan, Pakistan K2 Stone: Azurite Orbs in Pale Granite and the Geology Behind...
K2
Azurite-bearing granitic rock Quartz, feldspars, and mica Azurite: Cu3(CO3)2(OH)2 Malachite: Cu2CO3(OH)2 Composite hardness: approximately 3.5–7 Khaplu area, Gilgit-Baltistan, Pakistan K2 Stone: Azurite Orbs in Pale Granite and the Geology Behind...
Aventurine
Quartz with reflective mineral inclusions SiO2 Trigonal quartz structure Mohs approximately 6.5–7 Optical effect: aventurescence Fuchsite, hematite, goethite, ilmenite, and mica inclusions Aventurine: Quartz, Reflective Inclusions, and the Moving Light...
Aventurine
Quartz with reflective mineral inclusions SiO2 Trigonal quartz structure Mohs approximately 6.5–7 Optical effect: aventurescence Fuchsite, hematite, goethite, ilmenite, and mica inclusions Aventurine: Quartz, Reflective Inclusions, and the Moving Light...
Azurite
Copper carbonate hydroxide Cu3(CO3)2(OH)2 Monoclinic crystal system Mohs 3.5–4 Specific gravity approximately 3.7–3.9 Commonly associated with malachite Secondary copper mineral Azurite: Copper Blue, Oxidation-Zone Crystals, and the Slow Green Turn...
Azurite
Copper carbonate hydroxide Cu3(CO3)2(OH)2 Monoclinic crystal system Mohs 3.5–4 Specific gravity approximately 3.7–3.9 Commonly associated with malachite Secondary copper mineral Azurite: Copper Blue, Oxidation-Zone Crystals, and the Slow Green Turn...