Amethyst (Quartz)
Silicon Dioxide (SiO2) with iron impurities
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.
Amethyst (Quartz)
Silicon Dioxide (SiO2) with iron impurities
Citrine (Heat-treated or Natural Quartz)
Silicon Dioxide (SiO2)
Blue Apatite
Apatite - Ca5(PO4)3(F,Cl,OH)
Amethyst
Amethyst (Silicon Dioxide, SiO2 with Iron impurities)
Quartz Geode
Silicon Dioxide (SiO2)
Marble
Recrystallized Calcite (CaCO3)
Honey Calcite
Calcium Carbonate (CaCO3)
Ferruginous Quartz
Quartz with Iron Oxide inclusions (SiO2 + Fe2O3)
Quartz Geode (River Cobble)
Silicon Dioxide (SiO2)
Marble
Metamorphosed Limestone/Dolomite
Marble
Recrystallized Calcite (CaCO3)
Druzy Quartz (part of a Geode)
Silicon Dioxide (SiO2)
White Marble
Recrystallized Calcite (CaCO3)
Fluorite
Calcium Fluoride (CaF2)
Quartz (in a rock matrix)
Quartz (SiO2)
Yellow Calcite
Calcium Carbonate (CaCO3)
Amethyst
Amethyst (Quartz variety), Silicon Dioxide (SiO2)
Chert (Chalcedony/Agate variety)
Silicon Dioxide (SiO2)
Amethyst (Tumbled)
Silicon Dioxide (SiO2 with iron impurities)
Amethyst
Amethyst (Silicon Dioxide - SiO2 with iron impurities)
Amethyst (Rough Quartz)
Silicon Dioxide (SiO2 with Iron impurities)
Quartz (likely a macrocrystalline variety like milky quartz or smoky quartz, given the appearance in the image)
Quartz (SiO₂ - Silicon Dioxide)
Sandstone with Quartz Vein
Arenite with SiO2 intrusion
Quartzite (Iron-stained)
Quartzite (mostly SiO2 with Fe2O3 impurities)
Marble
Recrystallized Limestone (CaCO3)
Fluorite Tower
Fluorite (Calcium Fluoride - CaF2)
Marble
Recrystallized Calcite (CaCO3)
Limestone (Grey and White specimens)
Calcium Carbonate (CaCO3)
Chevron Amethyst
Silicon Dioxide (SiO2) with iron impurities
Painted River Rock
Anthropogenic-modified Siliciclastic Sedimentary Rock
Quartz
Silicon Dioxide (SiO2)
Orange Calcite
Calcium Carbonate (CaCO3)
Porphyry (likely Porphyritic Andesite or Basalt)
Porphyritic Igneous Rock
Quartzite Pebble
Meta-quartzite
Quartz
Silicon Dioxide (SiO2)
Banded Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Quartz
Quartz (SiO₂)
Amethyst (Geode)
Silicon Dioxide (SiO2) with iron impurities
Amethyst (Quartz)
Silicon Dioxide (SiO2) with Iron impurities
Purple Agate (Dyed Chalcedony)
SiO2 (Silicon Dioxide) with organic dyes
Charoite
Charoite (K(Ca,Na)2Si4O10(OH,F)·H2O)
Sandstone (lithic wacke/arenite)
Clastic sedimentary rock (primarily SiO2)