Black Limestone with Calcite Veining
Bituminous Limestone (CaCO3 with Organic Carbon inclusions)
Category
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Black Limestone with Calcite Veining
Bituminous Limestone (CaCO3 with Organic Carbon inclusions)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Graphite
Graphite (Carbon, C)
Graphite
Graphite (Native Carbon), Formula: C
Fossil Coral
Cnidaria Anthozoa (Fossilized)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Amber
Succinates (Organic compound: C10H16O)
Vesicular Basalt (Amygdaloidal)
Amygdaloidal Basalt (Mafic volcanic rock)
Sodalite Syenite
Sodalite-bearing Syenite (Na8(Al6Si6O24)Cl2)
Malachite
Malachite, Cu2(CO3)(OH)2
Banded Agate
Cryptocrystalline Quartz (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Greenstone (Epidisite / Chlorite Schist)
Metabasalt (often contains Epidote Ca2Al2(Fe3+,Al)(SiO4)(Si2O7)O(OH) and Chlorite)
Shale or Argillite
Shale (sedimentary) / Argillite (metamorphic)
Chert (Jasper variation)
Microcrystalline Quartz (SiO2)
Jasper Beads (Polished)
Silicon Dioxide (SiO2)
Jasper
Silicon Dioxide (SiO2)
Red Jasper
Jasper (Silicon Dioxide with Hematite inclusions), SiO2
Quartz (Druzy/Macro-crystalline)
Silicon Dioxide (SiO2)
Coral (Precious Coral)
Corallium rubrum (Red Coral), Paracorallium japonicum (Momo Coral), Pleurocorallium elatius (Sardinian Coral), various other species within the Corallidae family. Chemically, it's primarily Calcium Carbonate (CaCO 3 ).
Carnelian (a variety of Chalcedony)
SiO2 (Silicon Dioxide) - Cryptocrystalline Quartz
Tiger's Eye
Silicon dioxide (SiO2) with fibrous inclusions of crocidolite (riebeckite)
Clear Quartz
Silicon Dioxide (SiO2)
Red Jasper
Jasper (Silica/Silicon Dioxide, SiO2 plus iron inclusions)
Yellow Jasper
Jasper (Silicon Dioxide, SiO2 plus various mineral impurities)
Red Tiger's Eye beads
Tiger's Eye (variety of Chalcedony, SiO2)
Green Chalcedony (Green Agate)
Silicon Dioxide (SiO2)
Chert (often called Flint or River Rock)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Banded Agate
Cryptocrystalline Quartz (SiO2)
Diorite (Salt and Pepper Rock)
Diorite
Quartzite
Quartzite (primarily SiO2)
Quartzite
Meta-quartzite (SiO2)
Gold Ore in Matrix
Native Gold (Au) in Quartz/Limonite host rock
Azurite
Azurite - Copper Carbonate Hydroxide [Cu3(CO3)2(OH)2]
Banded Agate (specifically shades of Carnelian Agate)
Silicon Dioxide (SiO2)
Lepidolite in Quartz (Lithium-bearing Ore)
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2) and Quartz (SiO2)
Nephrite Jade / Greenstone
Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)
Dioptase
Dioptase (CuSiO3 · H2O)
Diorite
Phaneritic intermediate plutonic rock
Quartzite
Quartzite (primarily SiO2)
Kunzite
Spodumene (LiAlSi2O6), variety Kunzite
Jasper (Mookaite style)
Silicon Dioxide (SiO2) with iron and manganese inclusions