Iolite-bearing Gneiss (Cordierite)
Cordierite (Mg2Al4Si5O18) in Gneiss matrix
metamorphic
Category
Organic Gemstone (Not A Mineral)
Browse organic gemstone (not a mineral) specimens identified by the Rock Identifier community.
Moss Agate
Moss Agate (a variety of Chalcedony, SiO ₂)
Mineral (specifically a variety of Chalcedony, which is microcrystalline Quartz)
Fluorite and Red Jasper
Fluorite (Calcium Fluoride, CaF2) and Red Jasper (Silicon Dioxide, SiO2)
mineral
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
mineral
Rough Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Chalcedony (specifically Agate or Carnelian pebble)
Chalcedony (Microcrystalline Quartz, SiO2)
mineral
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Banded Agate
Cryptocrystalline Quartz (SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Almandine Garnet
Almandine (Fe3Al2Si3O12)
mineral
Blue Chalcedony
Chalcedony (cryptocrystalline Silicon Dioxide, SiO2)
mineral
Red Jasper
Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2)
mineral
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Amethyst
Crystalline Quartz (SiO2) with iron impurities
mineral
Garnet
Garnet Group (Silicate mineral); general formula X3Y2(SiO4)3
Mineral
Lace Agate (specifically Red Lace Agate)
Silicon Dioxide (SiO2) - variety of Chalcedony/Quartz
Mineral
Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Shale or Argillite
Shale (fine-grained clastic sedimentary rock) or Argillite (low-grade metamorphic rock derived from shale)
Sedimentary or Metamorphic (low grade)
Iolite (Cordierite)
Magnesium Iron Aluminum Silicate (Mg,Fe)2Al4Si5O18
mineral
Carnelian (a variety of Chalcedony)
Silicon Dioxide (SiO2) with iron oxide impurities
mineral
Peridot
Olivine (Mg,Fe)2SiO4
Mineral
Rough Diamond
Diamond (Native Carbon), C
mineral
Labradorite
Labradorite ((Ca, Na)(Al, Si)4O8)
mineral
Rough Quartz (with Feldspar inclusions)
Silicon Dioxide (SiO2)
Mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Celestite (Celestine)
Strontium sulfate (SrSO4)
mineral
Green Aventurine
Quartz (Aventurine variety) - SiO₂ with Fuchsite inclusions
Mineral
Prehnite
Prehnite, Ca2Al2Si3O10(OH)2
Mineral
Amethyst
Quartz (Silicon Dioxide) - SiO2
mineral
Pink Diamond
Carbon (C)
mineral
Chert (Jasper variety) with Iron Oxide staining
Cryptocrystalline Quartz (SiO2) with Goethite/Limonite impurities
sedimentary
Quartz (specifically Clear Quartz or Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Agate
Silicon dioxide (SiO2) - variety Chalcedony
mineral
Clear Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Red Jasper (River Polished)
Jasper (Silicon Dioxide, SiO2)
sedimentary/mineral
Lapis Lazuli
Complex metamorphic rock containing Lazurite ((Na,Ca)8(AlSiO4)6(SO4,S,Cl)2), Calcite, and Pyrite
metamorphic
Aquamarine
Beryl (Be3Al2Si6O18)
mineral
Yellow Calcite
Calcium Carbonate (CaCO3)
mineral
Quartz Crystal (specifically a milky or semi-translucent single crystal point)
Silicon Dioxide (SiO2)
mineral
Amethyst Geode
Silicon Dioxide (SiO2) with iron impurities
mineral