Chert Pebble (Jasperoid/Flint)
Silicon Dioxide (SiO2) - cryptocrystalline quartz
Category
Browse limestone specimens identified by the Rock Identifier community.
Chert Pebble (Jasperoid/Flint)
Silicon Dioxide (SiO2) - cryptocrystalline quartz
Chert (varieties include Flint or Jasper)
Chert (cryptocrystalline quartz; SiO₂)
Geode with Quartz and possibly Jasper/Hematite
Quartz (SiO2) and Chalcedony (cryptocrystalline SiO2), possibly stained by iron oxides
Cockle Shell (Fossil or Recent)
Class Bivalvia, Family Cardiidae (e.g., Cerastoderma edule for common cockle)
Chert / Flint
Chert (varietal name for microcrystalline quartz). Chemical formula: SiO₂
Chert
Chert (microcrystalline quartz, SiO2)
Fossil Coral
Fossilized Scleractinia or Tabulata (various genera/species)
Quartz Geode (likely within Limestone or Dolomite matrix)
Quartz (SiO₂)
Calcite (or Alabaster, if truly carved)
Calcium Carbonate (CaCO3)
Travertine (used in construction, not a 'specimen' in situ)
Travertine
Pyrite
Iron Pyrite (FeS₂)
Black Star Diopside (beads)
Diopside (CaMgSi2O6) - a member of the pyroxene group
Chert
Chert (variant of microcrystalline quartz)
Druzy Quartz on Matrix (likely Limestone or Sandstone)
Silicon Dioxide (SiO2) with various trace impurities
Fluorite (likely)
Calcium Fluoride (CaF2)
Chalk
Calcareous Ooze (composed primarily of coccoliths)
Dolomite
Dolomite (CaMg(CO3)2)
Green Glass Cullet / Recycled Glass
Amorphous Silicon Dioxide (SiO2) with various metal oxides
Lapis Lazuli
Lapis Lazuli (a rock, not a single mineral; primary mineral is Lazurite (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Calcite
Calcite (CaCO3)
Shale
Shale
Shale
Shale (fine-grained clastic sedimentary rock)
Calcite
Calcite (CaCO3)
Galena
Galena (Lead Sulfide), PbS
Quartzite
Quartzite
Chert (Jasper or Flint variant)
Chert (composed of microcrystalline quartz, SiO2)
Chert (often referred to as 'Jasper' when red)
Chert (microcrystalline quartz, SiO₂)
Azurite-Malachite (often a mixed specimen)
Azurite: Cu3(CO3)2(OH)2; Malachite: Cu2(CO3)(OH)2. The specimen appears to be a natural mixture or intergrowth of these two minerals.
Lapis Lazuli
A metamorphic rock primarily composed of lazurite (Na,Ca)8[(S,SO4,Cl)2|(Al6Si6O24)], calcite (CaCO3), and pyrite (FeS2).
Bivalve Shell (Fossil or Contemporary)
Class Bivalvie (various genera and species of clams, cockles, etc.)
Sodalite
Sodalite - Na8(Al6Si6O24)Cl2
White Jade (Nephrite)
Nephrite, Ca2(Mg,Fe)5Si8O22(OH)2
Talc
Talc (Mg₃Si₄O₁₀(OH)₂)
Chert / Flint
Chert (varieties include Flint)
Jade (likely Nephrite or Jadeite)
Nephrite (a variety of actinolite, Ca2(Mg,Fe)5Si8O22(OH)2) or Jadeite (NaAlSi2O6)
Flint
Chert (a form of cryptocrystalline quartz, chemical formula SiO₂)
Jade (Nephrite or Jadeite)
Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2) or Jadeite (Na(Al,Fe3+)Si2O6)
Pebble (river rock/beach pebble)
Pebble (clast size class)
Chert (or Flint)
Silicon dioxide (SiO2)
Black Chert
Chert (microcrystalline quartz)
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))