Crystal

Red Quartzite (Strawberry Quartz)

Quartzite (SiO2 with iron oxide inclusions)

Selenite (Satin Spar)

Gypsum (CaSO4·2H2O)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Rose Quartz Bead

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Rose Quartz

Quartz (Silicon Dioxide - SiO2)

Almandine Garnet in Matrix

Almandine, Fe3Al2(SiO4)3

Quartz (likely Clear Quartz or Rock Crystal)

Quartz (SiO2)

Polished Agate Geode

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal Fragments)

Silicon Dioxide (SiO2)

Rose Quartz

Silicon dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Quartz Geode

Silicon Dioxide (SiO2)

Pyrite Geode (Sparkling Druzy)

Iron Sulfide (FeS2) in Sedimentary Nodule

Epidote with Quartz

Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Gypsum (Selenite variety)

Calcium sulfate dihydrate (CaSO4·2H2O)

Titanium Coated Kyanite (Aura Kyanite)

Aluminosilicate (Al2SiO5) with a Titanium-Niobium vacuum-deposited coating

Unknown Rock Specimen

Quartz (Milky/Smoky Crystal fragment)

Silicon Dioxide (SiO2)

Amethyst Cluster

Silicon Dioxide with Iron impurities (SiO2)

Prase Quartz on Feldspar

Quartz (Silicon Dioxide, SiO2) with Hedenbergite inclusions on Potassium Feldspar (KAlSi3O8)

Rough Emerald

Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Druzy Agate (specifically Black Druzy Agate)

Silicon Dioxide (SiO2)

Pyrite in Matrix

Iron Disulfide (FeS2)

Quartz Druze on Matrix

Silicon Dioxide (SiO2)

Rose Quartz

Silicon dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Quartz Geode

Silicon Dioxide (SiO2) in a concretion

Satin Spar Selenite

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Desert Rose

Gypsum (CaSO4·2H2O) or Baryte (BaSO4) with trapped sand grains

Marble

Metamorphosed Limestone (main mineral: Calcite, CaCO3)

Obsidian

Volcanic Glass (SiO2, usually >70% silica content)

Porphyritic Basalt (Chinese Writing Stone)

Porphyritic Basalt or Porphyritic Andesite

Clear Quartz crystals on a Matrix base (Geode fragment)

Silicon Dioxide (SiO2)

Clear Quartz Crystal (Likely Golden Healer/Iron-Stained)

Silicon Dioxide (SiO2)

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Clear Quartz (Druzy/Crystal Cluster)

Silicon Dioxide (SiO2)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Dyed Agate Geode Slice

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Smoky Quartz

Silicon Dioxide (SiO2)

Quartz (Milky or Smoky)

Silicon Dioxide (SiO2)