Mineral Pseudomorph

Orange Calcite

Calcium Carbonate (CaCO3)

Satin Spar Selenite

Calcium Sulfate Dihydrate (CaSO4·2H2O)

Milky Quartz

Silicon Dioxide (SiO2)

Banded Agate (specifically Carnelian Agate)

Silicon dioxide (SiO2) - Chalcedony variety

Sandstone

Arenite (primarily SiO2)

Milky Quartz Geode with Chlorite

Silicon Dioxide (SiO2) with Chlorite group inclusions

Granite (with Beryl/Aquamarine)

Granite (Feldspar, Quartz, Mica, and Beryl Be3Al2Si6O18)

Sandstone (likely Graywacke or Lithic Sandstone)

Arenite / Wacke (SiO2 based with lithic fragments)

Sulfur

Native Sulfur (S8)

Raw Diamond (Rough Uncut)

Diamond (C - pure carbon)

Milky Quartz (Water-Worn Cobble)

Silicon Dioxide (SiO2)

Serpentine Schist with Quartz Vein

Serpentine Schist (a type of Metamorphic rock). The white band is likely Quartz (SiO2).

Amygdaloidal Basalt

Amygdaloidal Basalt

Snowflake Obsidian

Volcanic glass with Cristobalite inclusions (70–75% SiO2)

Meteorite (Chondrite)

Stony Meteorite (Ordinary Chondrite)

Calcite

Calcite (CaCO3)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Schist

Mica Schist (Quartz-Muscovite-Biotite Schist)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Bauxite (Concretionary)

Bauxite (Al(OH)3, AlO(OH))

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Metasedimentary or Igneous matrix

Milky Quartz Pebble with Chert

Silicon Dioxide (SiO2)

Quartz (Chert/Chunky Chalcedony)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Fluorite

Calcium Fluoride (CaF2)

Natural Gemstone Cabochons (Ruby, Moonstone, Emerald, Citrine)

Ruby (Al2O3:Cr), Moonstone (KAlSi3O8), Emerald (Be3Al2(SiO3)6:Cr), Citrine (SiO2)

Dendritic Siltstone (or Mudstone)

Siltstone with Manganese Oxide dendrites

Quartz (Milky/Clear Variety)

Silicon Dioxide (SiO2)

Jasper

Jasper (Silicon Dioxide, SiO2)

Mixed Quartz and Jasper Pebbles

Silicon Dioxide (SiO2)

Fluorite

Calcium Fluoride (CaF2)

Potassium Feldspar (Orthoclase)

KAlSi3O8

Obsidian

Volcanic Glass (SiO2 rich)

Fluorite

Fluorite (Calcium Fluoride - CaF2)

Quartz Pebble

Silicon Dioxide (SiO2)

River Quartz Cobble

Silicon Dioxide (SiO2)

Labradorite (Larvikite variety)

Plagioclase Feldspar (Na,Ca)(Si,Al)4O8

Pearl

Calcium Carbonate (primarily Aragonite and Calcite), CaCO3

Black Obsidian

Obsidian (Volcanic Glass)

Siltstone with iron staining

Siltstone (primarily SiO2 with FeO(OH) coatings)

Nephrite Jade

Ca2(Mg,Fe)5Si8O22(OH)2

Glauconitic Sandstone

Greensand (Glauconite-bearing sandstone)