Limestone
Calcareous sedimentary rock (primarily CaCO3)
Category
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Limestone
Calcareous sedimentary rock (primarily CaCO3)
Larimar
Pectolite (Sodium Calcium Silicate Hydroxide) - (NaCa2(Si3O8)(OH))
Pegmatite (Granitic)
Granitic Pegmatite containing Quartz, Feldspar, and Tourmaline (Schorl)
Quartz Pebble
Silicon Dioxide (SiO2)
Epidosite (Unakite-related)
Epidosite (predominantly Epidote, Ca2(Al2,Fe3+)(SiO4)3(OH))
Blue Calcite
Calcium Carbonate (CaCO3)
Orange Quartzite / River Pebble
Quartzite (primarily SiO2)
Carnelian and Mixed Agates
Cryptocrystalline Quartz (SiO2 with Iron Oxide impurities)
Quartzite
Quartzite (primarily SiO2)
Chert (Nodule)
Cryptocrystalline Silica (SiO2)
Banded Quartzite
Quartzite (primarily SiO2)
Quartzite Pebble
Quartzite (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)
Granite
Granite
Magnetite
Magnetite (Fe3O4)
Chert (also known as Flint or Common Chalcedony)
Cryptocrystalline Silica (SiO2)
Chert
Chert (Microcrystalline Quartz, SiO2)
Quartzite
Quartzite (mainly Silicon Dioxide, SiO2)
Graywacke with Quartz Veins
Argillaceous Sandstone (SiO2 composition in veins)
Quartzite (River Cobble)
Quartzite (SiO2)
Granite Pebble
Granite (Phaneritic intrusive igneous rock)
Tiger's Eye (Mineral Collection)
Tiger's Eye (SiO2 with crocidolite inclusions)
Stromatolite
Stromatolite (Cyanobacteria-formed Organo-sedimentary structure)
Talc
Talc (Mg₃Si₄O₁₀(OH)₂)
Sodalite
Na8(Al6Si6O24)Cl2 (Sodium Aluminum Silicate Chloride)
Quartzite
Quartzite (predominantly SiO2)
Quartzite River Pebble
Quartzite (primarily SiO2)
Hag Stone (Sandstone with Boreholes)
Bored Sandstone (Sedimentary rock with lithophaga-style borings)
Ironstone Concretion (Siderite Nodules)
Siderite (FeCO3) in Mudstone or Sandstone matrix
Amazonite
Microcline (K(AlSi3O8))
Micaceous Schist
Mica Schist (primarily Muscovite or Biotite KAl2(AlSi3O10)(OH)2)
Porphyry (Flower Stone)
Porphyry (Andesite or Basalt matrix)
Siltstone
Siltstone (SiO2, Fe2O3, Al2O3 mix)
Diorite
Diorite (intermediate intrusive igneous rock)
Quartzite
Quartzite (primarily SiO2)
Rough Green Calcite
Calcite (Calcium Carbonate, CaCO3)
Chert
Microcrystalline Quartz (SiO2)
Quartzite (Tumbled Pebble)
Quartzite (SiO2)
Limonite (Iron Stone)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
Green Calcite
Calcium Carbonate (CaCO3)
Chert (Black Flint)
Chert (Microcrystalline Quartz, SiO2)
Orange Quartz (Tangerine Quartz)
Silicon Dioxide (SiO2) with Hematite inclusions