Chalk
Calcium Carbonate (CaCO3)
Category
Browse synthetic polymer (polylactic acid) specimens identified by the Rock Identifier community.
Chalk
Calcium Carbonate (CaCO3)
Chert (Beach Pebble)
Silicon Dioxide (SiO2)
Limestone (Ocherous)
Calcium Carbonate (CaCO3) with Iron Oxide (Limonite)
Howlite (Tumbled)
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
Coquina or Fossiliferous Limestone
Biogenic Limestone (Calcite/Aragonite CaCO3)
River Pebble (Greywacke or Quartzite-rich Sandstone)
Lithic Sandstone (primarily SiO2 with rock fragments)
River Quartzite or Chert Pebble
Quartzite (primarily Silicon Dioxide - SiO2)
Rhodochrosite
Manganese Carbonate (MnCO3)
Quartz Pebble
Silicon Dioxide (SiO2)
Yellow Calcite
Calcium Carbonate (CaCO3)
Malachite
Copper(II) carbonate hydroxide [Cu2CO3(OH)2]
Riverstone Quartzite (Iron-stained)
Quartzite (primarily SiO2 with Limonite/Goethite staining)
Quartzite Pebble
Metamorphic Quartz (SiO2)
Coquina
Coquina Limestone
Copper-bearing Quartz (likely Malachite on Quartz matrix)
Cu2CO3(OH)2 (Malachite) on SiO2 (Quartz)
Honey Calcite
Calcium Carbonate (CaCO3)
Marble
Recrystallized Calcite (CaCO3)
Quartzite (River Pebble)
Metamorphic Quartzite (primarily SiO2)
Breciated Limestone with Calcite Veins
Sedimentary Breccia (CaCO3)
Quartz Pebble (Geode-like)
Silicon Dioxide (SiO2)
Orange Calcite
Calcium Carbonate (CaCO3)
Quartzite (River Stone)
Quartzite (SiO2)
Red Sandstone
Arenite (with Iron Oxide / Hematite cementation)
Sandstone with Calcite Vein
Clastic sedimentary rock (primarily SiO2) with Calcium Carbonate (CaCO3) infilling
Quartzite
Quartzite (primarily SiO2)
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Rhodochrosite with Pyrite and Quartz
Manganese Carbonate (MnCO3)
Quartz (specifically Milky or Rose Quartz variant)
Silicon Dioxide (SiO2)
Ocherous Sandstone (Ferruginous Sandstone)
Ferruginous Arenite (SiO2 with Fe2O3)
Marble
Recrystallized Carbonate Rock (CaCO3)
Yellow Calcite
Calcite (Calcium Carbonate, CaCO3)
Botryoidal Quartz / Calcite Geode crust
Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)
Honey Calcite (Orange Onyx)
Calcium Carbonate (CaCO3)
Coquina
Coquina (Bioclastic Limestone)
Tufa
Calcareous Tufa (CaCO3)
Quartzite
Quartzite (SiO2)
Limestone (Flagstone)
Fossiliferous Limestone (CaCO3)
Fossiliferous Limestone (Shell Fragment)
Biogenic Limestone (Calcium Carbonate / CaCO3)
Malachite
Copper(II) carbonate hydroxide [Cu2CO3(OH)2]
Dragon Blood Jasper
Epidote with Red Piedmontite (Chalcedony/Quartz variant)
Yellow Calcite
Calcium Carbonate (CaCO3)
Rhodonite
Rhodonite (Manganese silicate), (Mn,Fe,Mg,Ca)SiO3