Limestone
CaCO3 (principally Calcite)
Category
Browse man made byproduct (often mistaken for obsidian or emerald) specimens identified by the Rock Identifier community.
Limestone
CaCO3 (principally Calcite)
Quartz Pebble (often referred to as 'Sea Glass' or 'River Stone' when worn smooth)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Sandstone (Quartzose)
Arenite (primarily SiO2)
Bituminous Coal
Organic sedimentary rock (humic coal)
Aventurine (likely Green Aventurine)
Silicon Dioxide (SiO2) with various inclusions
Fluorite
Calcium Fluoride (CaF2)
Pyrite
Pyrite (Iron Disulfide), FeS2
Rhodonite
Rhodonite (Manganese Silicate), (Mn,Fe,Mg,Ca)SiO3
Rhodonite
Rhodonite (Manganese Iron Magnesium Calcium Silicate - (Mn,Fe,Mg,Ca)SiO3)
Iron-stained Quartzite
Recrystallized Quartz (SiO2) with Hematite/Limonite staining
Sandstone (Quartzite Pebble)
Arenite (primarily SiO2)
Jade (likely Nephrite Jade based on appearance)
Nephrite (a variety of actinolite, Ca2(Mg,Fe)5Si8O22(OH)2)
Basalt with Quartz Veins
Vesicular or aphanitic Basalt with SiO2 (Quartz) intrusions
Fluorite (likely Fluorite on Quartz/Matrix)
Calcium Fluoride (CaF2)
Vanadinite
Lead Chlorovanadate - Pb5(VO4)3Cl
Olivine (Peridot)
Olivine Group (Mg,Fe)2SiO4
Bronzite
MgSiO3 (Enstatite with 10-30% FeSiO3 in solid solution)
Sandstone (likely Arkosic)
Clastic Sedimentary Rock (primarily SiO2 with Feldspar)
Shale
Argillaceous Rock
Calcite
Calcium Carbonate (CaCO3)
Fluorite
Calcium Fluoride (CaF2)
Yellow Ochre / Limonite
Limonite (inter-mixed iron oxides and hydroxides, primarily FeO(OH)·nH2O)
Quartzite
Quartzite (SiO2)
Eclogite
Eclogite (Omphacite + Pyrope)
Hematite Nodule
Hematite (Fe2O3)
Sandstone (Quartzite Pebble)
Arenite (SiO2)
Sandstone
Arenite (SiO2 primarily)
Limestone
Calcium Carbonate (CaCO3)
Rough Corundum (Sapphire/Ruby mixture)
Corundum (Aluminum Oxide, Al2O3)
Pyrite
Iron Pyrite (FeS2)
Sandstone (Ferruginous)
Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)
Pearl (as a Biogenic Mineral)
Calcium Carbonate (mostly Aragonite) with Conchiolin; CaCO3
Sandstone (with Iron Staining)
Clastic Sedimentary Rock (primarily Quartz with Fe2O3 staining)
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
Diamond in Kimberlite
Diamond (C in Kimberlite)
Sandstone (Ferruginous)
Arenite (Fe-rich)
Gold Nugget
Native Gold (Au)
Turquoise, Pearl, and Coral Necklace
CuAl6(PO4)4(OH)8·4H2O (Turquoise) / CaCO3 (Pearl and Coral)
Red Sandstone
Arenite (Ferruginous Sandstone)
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Quartz Crystal
Silicon Dioxide (SiO2)