River Rock (Greywacke/Siltstone)
Siltstone / Argillaceous Greywacke
Category
Browse sedimentary or metamorphic (low grade) specimens identified by the Rock Identifier community.
River Rock (Greywacke/Siltstone)
Siltstone / Argillaceous Greywacke
Petrified Wood
Silicified Wood (SiO2)
Rainbow Moonstone
White Labradorite (formula: (Na,Ca)(Al,Si)4O8)
Desert Rose (Gypsum Variety)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
Green Quartzite
Quartzite (SiO2)
Shungite
Non-crystalline carbon (Fullerenes / Carbon-60)
Nephrite Jade
Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)
Lapis Lazuli
Na8[Al6Si6O24]n(S,Cl,SO4,OH)2 (Lazurite and other associated minerals)
Lapis Lazuli
Lapis Lazuli (Aggregate primarily of Lazurite: (Na,Ca)8(AlSiO4)6(S,SO4,Cl,1-2) with Calcite and Pyrite)
Quartzite (Yellow/Orange variety)
Quartzite (composed primarily of Silica, SiO2)
Nephrite Jade
Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)
Lapis Lazuli (polished cabochon/sphere)
Na8[Al6Si6O24]Sn with accessory minerals (Pyrite, Calcite)
Red Siltstone
Siltstone (composed mainly of SiO2 and Fe2O3)
Quartz (specifically Citrine or Iron-stained Quartz)
Silicon Dioxide (SiO2)
Black Spinel
Magnesium Aluminum Oxide (MgAl2O4)
Tanzanite
Blue Zoisite (Ca2Al3(SiO4)(Si2O7)O(OH))
Orthoclase Feldspar
Orthoclase (KAlSi3O8)
Serpentinite (Serpentine Rock)
Primarily composed of serpentine group minerals, such as antigorite, chrysotile, and lizardite. Chemical formula for serpentine minerals is (Mg,Fe)3Si2O5(OH)4.
Chert (Iron-stained)
Microcrystalline silica (SiO2) with trace Iron oxide (Fe2O3)
Nuummite
Nuummite (Ortho-amphibole rock, primarily Anthophyllite and Gedrite)
Charoite
Charoite (Hydrated potassium sodium calcium barium strontium silicate hydroxyfluoride)
Nephrite Jade
Ca2(Mg, Fe)5Si8O22(OH)2 (Tremolite-Actinolite series)
Serpentinite
Serpentinite (composed primarily of mineral group (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4)
Nephrite Jade
Calcium Magnesium Iron Silicate Hydroxide - Ca2(Mg,Fe)5Si8O22(OH)2
Carrara Marble
Metamorphosed Limestone (principally Calcium Carbonate, CaCO3)
Nephrite Jade
Ca2(Mg, Fe)5Si8O22(OH)2 (Tremolite-Actinolite series)
Eclogite
Eclogite (composed primarily of Omphacite and Pyrope Garnet)
Quartzite
Quartzite (primarily SiO2)
Tiffany Stone
Fluoritized Opal Beryllium Ore (principally Bertrandite, Be4Si2O7(OH)2)
Limestone Pebble
Sedimentary Calcium Carbonate (CaCO3)
Blue Sapphire
Corundum (Al2O3) with traces of Iron and Titanium
Sapphire (Corundum)
Corundum (Al2O3)
Shale or Mudstone (Based on appearance)
Shale (fine-grained, laminated fissile sedimentary rock) / Mudstone (fine-grained, non-fissile sedimentary rock)
Fluorite
Fluorite (Calcium Fluoride, CaF2)
Bloodstone Jasper (Heliotrope)
SiO2 (Silicon Dioxide) - Cryptocrystalline Quartz
Moonstone (Green Moonstone / Garnierite)
Potassium Aluminum Silicate (KAlSi3O8) with inclusions of Garnierite
Smoky Quartz
Quartz (Silicon Dioxide) - SiO2
Citrine
Silicon Dioxide (SiO2)
Moonstone
Orthoclase (Potassium aluminum silicate - KAlSi3O8)
Hypersthene
Hypersthene ((Mg,Fe)SiO₃)
Flint / Chert
Silicon dioxide (SiO2)
Banded Gneiss
Gneiss (pronounced 'nice')