Chert (with small quartz inclusion)
Microcrystalline Silica (SiO2)
Category
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Chert (with small quartz inclusion)
Microcrystalline Silica (SiO2)
Limestone
Calcium Carbonate (CaCO3)
Gold
Gold (Native Au)
Chert (Arrowhead/Projectile Point)
Microcrystalline quartz (SiO2)
Unknown Tumbled Stone
Unknown (Too Blurry)
Amethyst on Agate/Basalt Matrix
Silicon Dioxide (SiO2) with iron impurities
Sandstone
Arenite (SiO2 based with various mineral cements)
Conglomerate
Clastic Sedimentary Rock
Basalt
Basalt (Mafic Extrusive Igneous Rock)
Celestite (Celestine) Druze on Agate/Host Rock
Strontium sulfate (SrSO4)
Basalt
Basalt (extrusive volcanic rock)
Aquamarine
Beryl (Be3Al2Si6O18)
Quartzite Pebble
Quartzite (SiO2)
Quartzite pebble
Quartzite (SiO2)
Limonite Concretion
Goethite-Limonite (FeO(OH)·nH2O)
Rhodonite
Manganese Silicate (Mn, Fe, Mg, Ca)SiO3
Black Tourmaline
Schorl (Na(Fe²⁺)₃Al₆(OH)₄(BO₃)₃Si₆O₁₈)
Moqui Marble / Ironstone Concretion
Ironstone Concretion (Goethite/Hematite and Sandstone)
Chert (specifically Flint or Dark Chert)
Silicon Dioxide (SiO2)
Chert (Yellow/Tan)
Microcrystalline Quartz (SiO2)
Granite Pegmatite with Muscovite Mica
Granite Pegmatite (Silicon Dioxide and complex silicates)
Green Rutilated Quartz
Silicon Dioxide with Actinolite inclusions (SiO2 + Ca2(Mg,Fe)5Si8O22(OH)2)
Quartzite
Quartzite (SiO2)
Schist
Mica Schist
Pyrite (on Shale/Matrix)
Iron Disulfide (FeS2)
Quartzite
Quartzite (SiO2)
Quartzite
Quartzite (Primary mineral: Silicon Dioxide, SiO2)
Quartzite
Quartzite (SiO2)
Conglomerate
Conglomerate
Quartzite River Stone
Quartzite (SiO2)
Prehnite
Prehnite - Ca2Al(AlSi3O10)(OH)2
Hematite / Jasper
Iron(III) oxide (Fe2O3) in Quartz (SiO2)
Chrysocolla
Hydrated copper silicate (Cu,Al)2H2Si2O5(OH)4·nH2O
Blue Calcite
Calcium Carbonate (CaCO3)
Blue Sapphire
Corundum (Al2O3)
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) in Altered Host Rock
Chert
Chert (Microcrystalline Quartz)
Gold Nugget
Native Gold (Au)
Orange Calcite (Cleavage Rhomb)
Calcite (Calcium Carbonate, CaCO3)
Biological Bone (Patella/Knee)
Patella (part of the Human Skeletal System)
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)