Calcite
Calcite (Mineral; CaCO₃)
Mineral
Category
Sedimentary (Alluvial Deposit)
Browse sedimentary (alluvial deposit) specimens identified by the Rock Identifier community.
Sandstone (Weathered Pebble)
Arenite (composed primarily of SiO2)
sedimentary
Howlite
Howlite (Ca2B5SiO9(OH)5)
mineral
Chert (varietal known as Jasper or Flint)
Silicon Dioxide (SiO2)
Sedimentary Rock
Chert / Flint
Chert (varietal name for microcrystalline quartz). Chemical formula: SiO₂
Mineral
Manganese Ore (Psilomelane/Pyrolusite)
Psilomelane ((Ba,H2O)2Mn5O10) and Pyrolusite (MnO2)
Mineral
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Satin Spar (Selenite)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
mineral
Milky Quartz
Quartz (SiO2)
Mineral
Ocean Jasper
Silicon Dioxide (SiO2) with various inclusions
igneous/sedimentary mixed (Orbicular Jasper)
Chert Pebble/Nodule
Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)
Sedimentary
Red Jasper (Quartz)
Silicon Dioxide (SiO2) with Iron impurities
sedimentary
Red Jasper or Chert
Jasper (SiO2, a variety of chalcedony with iron oxide impurities), Chert (SiO2)
sedimentary
Sapphire
Corundum (Al₂O₃) with trace elements causing color variations.
Mineral
Aventurine
Aventurine Quartz (SiO2 with inclusions)
Mineral
Limonite (Iron Ore)
Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)
Mineral
Rock Salt / Halite Crust
Halite (Sodium Chloride, NaCl)
sedimentary
Howlite
Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)
mineral
Celestine (Celestite)
Strontium sulfate (SrSO4)
mineral
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
mineral
Chert (Yellow Jasper/River Pebble)
Microcrystalline Quartz (SiO2)
sedimentary
Ruby in Zoisite
Ruby (α-Al2O3) embedded in Zoisite (Ca2Al3(SiO4)3(OH)) with some Hornblende
Metamorphic Rock (composed of multiple minerals)
Sandstone (Water-worn)
Arenite
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Diamond
Diamond (C)
Mineral
Garnet (likely Pyrope or Almandine)
Garnet Group (complex nesosilicate minerals, e.g., Pyrope Mg3Al2(SiO4)3, Almandine Fe3Al2(SiO4)3, Spessartine Mn3Al2(SiO4)3, Grossular Ca3Al2(SiO4)3, Andradite Ca3Fe2(SiO4)3, Uvarovite Ca3Cr2(SiO4)3). The vivid red color in the image strongly suggests Pyrope or Almandine.
Mineral
Red Jasper
Microcrystalline quartz (SiO2) with Hematite (Fe2O3) impurities
sedimentary
Chert (Agatized/Chalcedony variety)
Microcrystalline Quartz (SiO2)
sedimentary
Leopard Skin Jasper
Chalcedony (cryptocrystalline Quartz)
Mineral
Sandstone
Quartz Arenite (a type of sandstone composed of more than 90% quartz)
Sedimentary Rock
Galena
Galena (Lead Sulfide), PbS
mineral
Mixed Gemstone Bracelet
Mixed natural minerals and rocks (e.g., Rhodonite, Malachite, Sodalite, Rose Quartz, Black Tourmaline, Quartz/Chalcedony variants)
Mineral/Rock assemblage
Sandstone (Water-worn Pebble)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
mineral
Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur).
Galena (PbS)
mineral
Satin Spar (Gypsum)
Hydrous Calcium Sulfate (CaSO4·2H2O)
mineral
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
White Precious Opal
Hydrated Silica (SiO2·nH2O)
mineral
Banded Calcite or Travertine
Calcium Carbonate (CaCO3)
Sedimentary
Pyrite (on the right) and Magnetite or Hematite (on the left)
Iron Sulfide (FeS2) and Iron Oxide (Fe3O4 or Fe2O3)
mineral
Limonite (Iron Ore)
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
mineral
Jasper
Silicon Dioxide (SiO2) - a variety of Chalcedony (Cryptocrystalline Quartz)
Mineral