Fluorite in Matrix
Fluorite (CaF2) within a host rock matrix
Category
Browse sedimentary or igneous fragment specimens identified by the Rock Identifier community.
Fluorite in Matrix
Fluorite (CaF2) within a host rock matrix
Fluorite
Fluorite (Calcium Fluoride, CaF2)
Gneiss
Gneiss (Metamorphic rock of variable composition, typically SiO2 rich)
Quartz
Quartz (SiO2 - Silicon Dioxide)
River Cobble (likely Basalt or Chert)
Siliceous River Rock / Microcrystalline Quartz / Mafic Igneous
Muscovite Mica
Muscovite (Potassium Aluminum Silicate Hydroxide Fluoride), KAl2(AlSi3O10)(OH,F)2
Obsidian and Green Calcite
Volcanic Glass and Calcium Carbonate (CaCO3)
Laterite
Laterite (no specific mineral formula as it's a rock type)
Sandstone (Pebble/Cobble)
Sandstone (arenite is a more precise term for sandstone with less than 15% matrix; this specimen appears to be a lithic or quartz arenite)
Quartz (River Pebble)
Quartz (SiO₂ - Silicon Dioxide)
Orthoclase Feldspar
Orthoclase (KAlSi3O8)
Biotite Mica
Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)
Gneiss
Gneiss (High-grade regional metamorphic rock)
Calcite
Calcite (CaCO3)
Carnelian
Carnelian (a variety of Chalcedony, SiO ₂)
Peridot and Citrine Gemstones (in a ring setting)
Peridot (Olivine: (Mg,Fe)2SiO4), Citrine (Quartz: SiO2)
Quartz (likely milky/gray variety)
Quartz (SiO₂)
Chalcedony (Banded/Mottled Variety)
Chalcedony (a cryptocrystalline variety of Quartz, SiO2)
Muscovite Mica
Muscovite (KAl₂(AlSi₃O₁₀)(F,OH)₂))
Clear Quartz (Rock Crystal)
Quartz (SiO₂)
Quartz
Silicon Dioxide (SiO2)
Agate (specifically, likely a geode slice or nodule)
Agate (a variety of Chalcedony, with chemical formula SiO2)
Quartz (Rock Crystal)
Quartz (SiO₂ - Silicon Dioxide)
Quartz
Quartz (SiO₂)
Banded Rock (likely Quartz-rich)
Uncertain, likely a Metamorphic Rock (e.g., Gneiss or Schist) with prominent Quartz and other minerals
Gneiss (Metamorphic Rock)
Gneiss
Mica (likely Muscovite)
Muscovite / KAl2(AlSi3O10)(OH)2
Magnetite
Magnetite (Fe3O4)
Pyrite
Pyrite (FeS2)
Lapis Lazuli
Lapis Lazuli (a rock composed primarily of Lazurite)
Pyrite (or Fool's Gold)
Pyrite (FeS₂)
River Rock (likely Basalt or Greywacke)
Basalt or Lithic Sandstone
Botryoidal Chalcedony
Chalcedony (SiO2)
River Stone (likely Basalt or Chert)
Silicon Dioxide (SiO2) for chert or Mafic Extrusive Rock for basalt
Wishing Stone (Basalt or Siltstone with Quartz/Calcite Vein)
Basalt (SiO2+MgO+FeO) or Siltstone with a Quartz (SiO2) or Calcite (CaCO3) vein
Granite (phaneritic background) with Limestone/Calcite carving
Felsic Igneous Plutonic Rock (background) / Calcium Carbonate (CaCO3) (carving)
Quartz
Quartz (SiO₂ - Silicon Dioxide)
Hematite (beads)
Hematite (Fe₂O₃)
Calcite
Calcite (CaCO₃)
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.
Green Aventurine and Clear Quartz
Green Aventurine (Silicon Dioxide - SiO2 with Fuchsite inclusions); Clear Quartz (Silicon Dioxide - SiO2)
River Pebbles (Tumbled Quartz and Basalt)
Silicon Dioxide (SiO2) for white quartz; Mafic Volcanic Rock for basalt