Greywacke (River Pebble)
Greywacke sandstone with quartz veining
Category
Browse organic gemstone (not a rock or mineral in the traditional sense, but bio mineralized material) specimens identified by the Rock Identifier community.
Greywacke (River Pebble)
Greywacke sandstone with quartz veining
Sunstone (variety of Feldspar)
Oligoclase Sunstone, Plagioclase Feldspar (Na,Ca)Al(Si,Al)Si2O8
Granite
Granite
Granite
Granite (a felsic intrusive igneous rock)
Garnet-Mica Schist
Schist (variety with Almandine Garnet, Fe3Al2(SiO4)3)
Amazonite
Amazonite (KAlSi3O8, a variety of Microcline)
Schist
Schist
Jasper
Silicon dioxide (SiO2)
Brecciated Jasper
Silicon Dioxide (SiO2) with varying mineral inclusions (Iron Oxide, Hematite, Clay)
Brachiopod Fossil (Spiriferid)
Order Spiriferida (Phylum Brachiopoda); mineralized as Calcite (CaCO3) or Chert (SiO2)
Conglomerate
Conglomerate (a clastic sedimentary rock)
Diamond
Diamond (C)
Red Jasper (Opaque Chalcedony)
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions
Mahogany Obsidian
Obsidian (Volcanic Glass) with Hematite/Magnetite inclusions
Labradorite
Labradorite (a variety of Plagioclase Feldspar), Na(AlSi3O8) to Ca(Al2Si2O8)
Laterite (iron-rich nodule, possibly Bauxite as a subtype)
Laterite (composed of various minerals including goethite, hematite, gibbsite, etc.)
Rutilated Quartz
Quartz (SiO2) with Rutile (TiO2) inclusions
Diamond
Diamond (C)
Quartz (Milky Quartz)
Quartz (SiO2 - Silicon Dioxide)
Fire Agate (Rough)
Silicon Dioxide (SiO2) - Variety of Chalcedony
Red Jasper
Opaque microcrystalline Quartz (SiO2 with Fe2O3 inclusions)
Aventurine (likely Green Aventurine)
Silicon Dioxide (SiO2) with mineral inclusions
Clear Quartz (Rock Crystal)
Quartz (Silicon Dioxide - SiO2)
Charoite
Charoite (Hydrated silicate of potassium, sodium, calcium, barium and strontium): (K,Sr,Ba)(Na,Ca)2[Si4O10](OH,f)·H2O
Chert (often referred to as 'Jasper' when red)
Chert (microcrystalline quartz, SiO₂)
Epidosite (Epidote-rich rock)
Epidotalite (primarily Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH))
Jasper
Silicon Dioxide (SiO2)
Basalt with Olivine Phenocrysts
Porphyritic Basalt (Mineral formula of Olivine: (Mg,Fe)2SiO4)
Agate
Agate (a cryptocrystalline variety of Quartz, SiO₂)
Granite
Phaneritic Intrusive Igneous Rock (primarily composed of SiO2, Al2O3, K2O, Na2O)
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)
K2 Azurite Granite / K2 Stone
Granite (igneous rock) with Azurite inclusions (mineral)
Banded Iron Formation (BIF) with Quartz
Banded Iron Formation, often composed of alternating layers of hematite (Fe2O3) or magnetite (Fe3O4) and chert (microcrystalline quartz, SiO2)
River Cobble (likely Sandstone or Siltstone type)
Sandstone or Siltstone (common rock types that form river cobbles)
Granite
Phaneritic Igneous Rock (composed primarily of Quartz SiO2, Alkali Feldspar (K,Na)AlSi3O8, and Plagioclase Feldspar)
Larimar
Pectolite (a blue variety of Pectolite)
Epidote (likely Pistacite in Epidosite rock)
Epidote: Ca2(Al,Fe)3(SiO4)3(OH)
Raw Emerald in Schist Matrix
Beryl (Be3Al2Si6O18) in Mica Schist
Mica Schist
Mica Schist (predominantly composed of Muscovite or Biotite silicates)
Blue Chalcedony and Picture Jasper Beads
Blue Chalcedony (SiO2), Picture Jasper (SiO2)
Lapis Lazuli
Lapis Lazuli (a rock composed primarily of Lazurite, Sodalite, Calcite, and Pyrite)
Limonite (Ironstone)
Hydrous ferric oxides (FeO(OH)·nH2O)