Moss Agate
Silicon Dioxide (SiO2) with inclusions
mineral
Category
Mineral, Specifically A Rock Fragment
Browse mineral, specifically a rock fragment specimens identified by the Rock Identifier community.
Arkosic Sandstone
Arkose (Clastic Sedimentary Rock)
sedimentary
Coquina or Fossilized Shell Aggregate
Calcareous bioclastic sedimentary rock (CaCO3)
sedimentary
River Cobble (likely Quartzite or Limestone)
SiO2 (Quartzite dominant) or CaCO3 (Limestone dominant)
metamorphic or sedimentary
Green Quartz (Aventurine)
Silicon Dioxide with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
mineral
Green Kyanite
Kyanite (Al2SiO5)
mineral
Carnelian
Carnelian (SiO2)
mineral
Red Sandstone
Arenite (predominantly SiO2 with Fe2O3)
sedimentary
Red Sandstone
Clastic Terrigenous Sedimentary Rock (typically Hematitic Quartz Arenite or Arkose)
sedimentary
Chert (Tan/Grey variety)
Silicon Dioxide (SiO2)
sedimentary
Soapstone / Steatite
Steatite (primarily Talc, Mg3Si4O10(OH)2)
metamorphic
Labradorite
Labradorite (Plagioclase Feldspar Series: (Ca,Na)(Al,Si)4O8)
mineral
Coquina or Fossiliferous Limestone
Biogenic Limestone (Calcite/Aragonite CaCO3)
sedimentary
Coquina (Fossiliferous Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Larimar
Pectolite (NaCa2Si3O8(OH))
mineral
Citrine
Silicon Dioxide (SiO2) with iron impurities
mineral
Rose Quartz
SiO2 (Silicon Dioxide)
mineral
Ocean Jasper
Silicon Dioxide (SiO2) - Orbicular Jasper / Chalcedony
mineral
Citrine Quartz
Citrine (Silicon Dioxide, SiO2)
mineral
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Aragonite Star Cluster
Aragonite (Calcium Carbonate, CaCO3)
mineral
Polygenetic Breccia
Clastic Breccia (containing lithic fragments in a fine-grained matrix)
sedimentary
Chrysoprase
Chrysoprase (a variety of Chalcedony, SiO₂)
Mineral
Ruby (Corundum)
Corundum (Aluminum Oxide with Chromium), Al2O3:Cr
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Transit Token (RTD Denver)
Nickel-plated brass or bronze alloy (Cu-Sn-Zn-Ni)
not a rock or mineral (anthropogenic material)
Agate (specifically, multi-colored or pastel-dyed agate)
Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).
Mineral
Fossiliferous Limestone
Limestone with fossil inclusions (CaCO3)
sedimentary
Black Tourmaline
Schorl (Sodium Iron Aluminum Borosilicate Hydroxide)
mineral
Baroque Pearl
Biogenic Calcium Carbonate (Aragonite/Conchiolin)
mineral
Banded Agate
Cryptocrystalline Quartz (SiO2)
mineral
Turquoise and Red Coral (with Grizzly Bear Claw)
Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Precious Coral (Corallium rubrum)
mineral
Coquina
Bioclastic Limestone
sedimentary
Red Sandstone
Arenite (primarily Quartz with Hematite cement)
sedimentary
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
mineral
Amazonite
K(AlSi3O8) - Microcline (Var. Amazonite)
mineral
Shungite
Shungite (carbon-rich Precambrian mineraloid)
mineral
Peach Moonstone
Potassium Aluminum Silicate (KAlSi3O8)
mineral
Greenschist
Greenschist (Chlorite-actinolite schist)
metamorphic
Conglomerate
Conglomeratic Sandstone / Sedimentary Breccia
sedimentary
Jasper (Chocolate or Brown Jasper)
Silicon Dioxide (SiO2)
sedimentary
Fossiliferous Limestone (Coquina / Shell Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary