Chert (Jasper and Chalcedony)
Silicon Dioxide (SiO2)
Category
Browse the purple specimen is a mineral (amethyst); the white specimen is a sedimentary rock (limestone or marble). specimens identified by the Rock Identifier community.
Chert (Jasper and Chalcedony)
Silicon Dioxide (SiO2)
Howlite and Purple Amethyst Druzy
Calcium Borosilicate Hydroxide (Howlite) and Silicon Dioxide (Quartz/Amethyst)
Quartz Druzy on Geode Fragment
Silicon Dioxide (SiO2)
Druzy Quartz on Matrix (likely Limestone or Sandstone)
Silicon Dioxide (SiO2) with various trace impurities
Quartz Geode
Silicon Dioxide (SiO2)
Amethyst Geode
Amethyst (Silicon Dioxide, SiO2)
Vesicular Basalt with Secondary Mineral Infill
Mafic Volcanic Rock (Basalt)
Amethyst (Quartz variety)
Silicon Dioxide (SiO2) with iron impurities
Marble
Recrystallized Calcite (CaCO3) or Dolomite (CaMg(CO3)2)
Citrine Quartz (likely heat-treated)
Silicon Dioxide (SiO2)
Quartz
Silicon dioxide (SiO₂)
Marble
Marble (primarily Calcite, CaCO3 or Dolomite, CaMg(CO3)2)
Calcite
Calcite (CaCO₃)
Blue Apatite
Fluorapatite / Chlorapatite [Ca5(PO4)3(F,Cl,OH)]
Optical Calcite (Iceland Spar)
Calcite (Calcium Carbonate, CaCO3)
Zebra Rock / Zebra Marble
Banded Limestone-Marble Transition
Quartzite with Quartz Veining
Quartzite (primarily SiO2)
Optical Calcite (Iceland Spar)
Calcite (Calcium Carbonate, CaCO3)
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Calcite
Calcium Carbonate (CaCO3)
Quartz (possibly milky quartz)
Quartz (Silica; SiO₂)
Chert / Chalcedony (likely carnelian or flint variety)
Silicon Dioxide (SiO2)
Amethyst (Tumbled Quarz)
Silicon Dioxide (SiO2) with iron impurities
Lapis Lazuli
Lapis Lazuli (Rock containing Lazurite (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2, Pyrite, and Calcite)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Amethyst (Rough Quartz)
Silicon Dioxide (SiO2) with iron impurities
Chert Pebble with Quartz Veins
Microcrystalline Quartz (SiO2)
Chert (Brecciated Chert)
Silicon Dioxide (SiO2)
Amethyst
Silicon Dioxide with Iron impurities (SiO2 + Fe3+)
Quartz
Silicon Dioxide (SiO2)
Chert (Nodular)
Microcrystalline Silica (SiO2)
Sandstone (Banded)
Clastic Sedimentary Rock (primarily SiO2)
Lapis Lazuli (Tumbled Stone)
Na6Ca2(Al6Si6O24)(SO4,S,Cl)2 (Lazulite-rich Metamorphic Rock)
Chert (Chalcedony/Agate)
Microcrystalline Quartz (SiO2)
Quartz
Quartz (SiO2 - Silicon Dioxide)
Chevron Amethyst
Silicon Dioxide (SiO2) with trace Iron (Fe4+)
Marble
Recrystallized Calcite (CaCO3)
Fluorite
Fluorite (Calcium Fluoride, CaF2)
Yellow Quartz (Citrine or Yellow Jasper)
Silicon Dioxide (SiO2)
Quartz
Quartz (SiO₂)
Marble
Recrystallized Calcite (CaCO3) / Marble
River Quartz Pitting / Quartzite Pebble
Quartzite (primarily SiO2)