Mineral Precipitate (Anthropogenic Context)

Amethyst Geodes

Silicon Dioxide (Quartz with Iron impurities), SiO2

Brecciated quartz-rich rock (probable vein breccia)

Hydrothermal quartz breccia; predominantly SiO₂ quartz clasts in iron-oxide-rich cement

Honey calcite (yellow calcite)

Calcite, CaCO₃

Likely quartz fragment

Quartz (silicon dioxide, SiO₂)

Pyrite-bearing quartz specimen

Pyrite (FeS₂) with quartz (SiO₂), possibly minor chalcopyrite or iron oxides

Yellow calcite (likely honey/yellow calcite)

Calcite, calcium carbonate (CaCO₃)

Selenite (satin spar gypsum)

Gypsum, CaSO₄·2H₂O; fibrous variety commonly called satin spar

Tumbled yellow calcite

Calcite (CaCO₃), likely honey or lemon calcite

Celestite (Celestine) Druze on Agate/Host Rock

Strontium sulfate (SrSO4)

Tumbled Yellow Chalcedony / Iron-Stained Quartz

Silicon Dioxide (SiO2)

Blue calcite

Calcite (CaCO₃), likely blue calcite with minor matrix minerals

Tumbled blue calcite

Calcite (CaCO₃), likely blue variety

Tumbled milky quartz (likely chalcedony or quartzite)

Quartz/chalcedony, silicon dioxide (SiO₂)

Satin Spar (often marketed as Selenite)

Fibrous Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Milky or Iron-Stained Quartz

Quartz (Silicon Dioxide, SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Quartz (Vein Quartz)

Silicon Dioxide (SiO2)

Agate (specifically Lace Agate or Banded Agate)

Silicon Dioxide (SiO2)

Potassium-Rich Silicate Clay (inferred from biological context)

Phyllosilicate group (likely Illite or Smectite within surrounding soil substrate)

Banded Iron Formation (BIF) or similar banded sedimentary rock

Banded Iron Formation

Chert (Flint Nodule)

Microcrystalline quartz (SiO2)

Jasper

Silicon Dioxide (SiO2)

Larimar

Pectolite (NaCa2Si3O8(OH))

Calcite crystal cluster

Calcite — calcium carbonate, CaCO₃

Druzy quartz-bearing rock

Quartz, SiO₂, as a druse coating or quartz-rich vein material

Clear quartz crystal

Quartz (silicon dioxide, SiO₂), likely milky or included rock crystal

Tumbled fluorite (probable)

Fluorite, calcium fluoride (CaF₂)

Green Agate

Cryptocrystalline Quartz (SiO2)

Red calcite

Calcite (CaCO₃), likely iron- or manganese-colored

Chalcedony (specifically Agate or Flint)

Silicon Dioxide (SiO₂)

Quartz (Clear/Smoky Geode fragment)

Silicon Dioxide (SiO2)

Desert Rose

Gypsum rosette (CaSO4·2H2O) or Barite rosette (BaSO4)

Fluorite (specifically Blue John or Banded Fluorite)

Calcium Fluoride (CaF2)

Carnelian Agate Beads

Silicon Dioxide (SiO2)

Milky quartz (rough quartz specimen)

Quartz, silicon dioxide (SiO₂)

Rough Quartz Crystal in Matrix

Silicon Dioxide (SiO2)

Quartz fragment

Silicon Dioxide (SiO2)

Limonite (Ironstone)

Hydrated Iron(III) Oxide-hydroxide (FeO(OH)·nH2O)

Polished orange calcite sphere

Calcite (CaCO₃), likely honey/orange calcite

Goldstone

Avventurina (Man-made Glass with Copper inclusions)

Honey calcite (orange calcite)

Calcite, calcium carbonate (CaCO₃)