Pebble
Clast (specifically a granule or small pebble)
Category
Browse mineral (man enhanced) specimens identified by the Rock Identifier community.
Pebble
Clast (specifically a granule or small pebble)
Marble
Marble (metamorphosed limestone/dolostone). Predominantly composed of Calcite (CaCO3) for marble derived from limestone, or Dolomite (CaMg(CO3)2) for marble derived from dolostone.
Amethyst Geode
Quartz (SiO₂) with iron impurities
Serpentine
Serpentine Group Minerals (e.g., Antigorite, Chrysotile, Lizardite)
Cobaltoan Calcite / Pink Dolomite (Possible)
Cobaltoan Calcite: (Ca,Co)CO3; Pink Dolomite (or Thulite): CaMg(CO3)2 or Mn-Dolomite / (Thulite: Mn2+3Al2(Si2O7)(SiO4)O(OH))
Shale or Argillite
Shale (fine-grained clastic sedimentary rock) or Argillite (low-grade metamorphic rock derived from shale)
Chert (or Flint)
Silicon dioxide (SiO2)
Scoria (Volcanic Rock)
Scoria (often basaltic scoria)
Marble
Metamorphosed Limestone/Dolomite
Sandstone
Sandstone (Clastic Sedimentary Rock)
Quartzite
Quartzite (primarily composed of SiO O₂)
Mother of Pearl (Nacre)
Calcium Carbonate (primarily aragonite, with conchiolin)
Serpentinite
Serpentinite (a rock composed predominantly of serpentine group minerals)
Banded Chert / Banded Jasper (likely a variety of Chert/Chalcedony)
Chert (microcrystalline quartz)
Quartz
Quartz (SiO2 - Silicon Dioxide)
Quartzite
Quartzite
Red Coral
Corallium rubrum (for precious red coral), although other species like Corallium japonicum and Paracorallium are also used.
Sea Glass (Frosted Glass)
Amorphous Silica (SiO2) with various additives