Amazonite
Microcline (KAlSi3O8) with Trace Lead
Category
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Amazonite
Microcline (KAlSi3O8) with Trace Lead
Rose Quartz
Silicon Dioxide (SiO2) with inclusions of Dumortierite or similar minerals
Quartzite
Quartzite (SiO2)
Blue Slag Glass
Amorphous Silica (Industrial byproduct)
Limonite (Iron-rich Siltstone / Sandstone base)
Hydrous ferric oxide mixture (FeO(OH)·nH2O)
Banded Iron Formation (BIF) / Tiger Iron
Banded Iron Formation containing Hematite (Fe2O3) and Magnetite (Fe3O4)
Pyrite
Iron Sulfide (FeS2)
Milky Quartz
Quartz (Silica / Silicon Dioxide, SiO2)
Quartzite
Quartzite (primarily SiO2)
Sandstone
Arenite (primarily SiO2)
Amygdaloidal Rhyolite (often called Lake Superior Agate relative)
Rhyolite with Calcite/Quartz amygdules (SiO2 and secondary minerals)
Chert (or possibly Flint)
SiO2 (Silicon Dioxide)
Chrysocolla in Quartz (Quantum Quattro variant)
Hydrated copper silicates (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O) often mixed with SiO2
Quartz (Smoky/Milky variety)
Silicon Dioxide (SiO2)
Orange Calcite
Calcium Carbonate (CaCO3)
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Quartzite Pebble
Metamorphic Quartzite (SiO2)
Quartzite
Quartzite (SiO2)
Raw Diamond
Diamond (pure Carbon, C)
Chert / Flint
Silicon Dioxide (SiO2)
Quartzite
Quartzite (Primary mineral: SiO2)
Limestone
Calcium Carbonate (CaCO3)
Milky Quartz (Pebble)
Silicon Dioxide (SiO2)
Amazonite
Amazonite (KAlSi3O8 - Microcline)
Milky Quartz
Silicon Dioxide (SiO2)
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Amethyst and Citrine (Quartz variants)
Silicon Dioxide (SiO2)
Agate Geode
Chalcedony (cryptocrystalline SiO2)
Jasper with Quartz
Silicon Dioxide (SiO2) - Chalcedony variety
Sandstone (Quartz Arenite)
Sandstone (dominated by SiO2 quartz grains)
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
Mica Schist
Mica Schist (primarily Muscovite and Quartz)
Drupa Quartz (Sparkly Drusy Quartz on Matrix)
Crystalline Silicon Dioxide (SiO2) on host rock
Quartz Pebble
Silicon Dioxide (SiO2)
Conglomerate
Clastic Sedimentary Conglomerate (SiO2, CaCO3, etc.)
Blue Slag Glass
Amorphous Silica (Byproduct of smelting)
Quartz Pebble
Silicon Dioxide (SiO2)
Granite Cobble (River Stone)
Felsic intrusive igneous rock (composition: Quartz, Feldspar, Mica)
Milky Quartz
Silicon Dioxide (SiO2)
Jasper and Ironstone (likely Jasperized Ironstone)
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)