Organic Gemstone (Not A Rock)

Epidote (likely Pistacite in Epidosite rock)

Epidote: Ca2(Al,Fe)3(SiO4)3(OH)

Granite (weathered pebble)

Granite (plutonic igneous rock)

Granitic Pegmatite

Coarse-grained Igneous Rock (Granitic composition: KAlSi3O8, SiO2)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Fluorite and Rose Quartz

Fluorite (CaF2), Rose Quartz (SiO2)

Snowflake Obsidian

Volcanic Glass with Cristobalite inclusions

Granite Gneiss with Garnet

Garnetiferous Gneiss

Goldstone

Not a natural mineral or rock. It is an ornamental glass.

Amethyst

Silicon Dioxide (SiO2) with trace Iron impurities

Almandine Garnet

Almandine (Fe3Al2(SiO4)3)

Chrome Diopside

Magnesium Calcium Silicate (MgCaSi2O6) containing Chromium impurities

Lapis Lazuli

Lapis Lazuli (a rock, not a single mineral; primary mineral is Lazurite (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2

Blue Apatite

Fluorapatite / Chlorapatite [Ca5(PO4)3(F,Cl,OH)]

Banded Chert in Matrix

Microcrystalline Quartz (SiO2)

Clear Quartz (Rock Crystal)

Quartz (Silicon Dioxide - SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Turquoise

Hydrous phosphate of copper and aluminum (CuAl6(PO4)4(OH)8·4H2O)

Rough Corundum (likely Sapphire/Zircon-bearing)

Aluminium Oxide (Al2O3)

Almandine Garnet in Schist Matrix

Almandine - Fe3Al2(SiO4)3

Biological Specimen (Domestic Dog)

Canis lupus familiaris

Quartzite

Quartzite (SiO2)

Stichtite (often found in Serpentinite)

Stichtite Mg6Cr2CO3(OH)16·4H2O

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Chert (Polished Gemstone / River Stone)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Green Quartzite

Metamorphic rock primarily composed of Silicon Dioxide (SiO2) with mineral inclusions like fuchsite or chlorite

Smoky Quartz

Silicon Dioxide (SiO2)

Chrysoprase

Chalcedony (cryptocrystalline SiO2 variety)

Smoky Quartz

Silicon Dioxide (SiO2)

Chert (Jasper variety)

Cryptocrystalline quartz (SiO2)

Clear Quartz (Crystal Quartz)

Silicon Dioxide (SiO2)

Epidote

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

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Amethyst (Tumbled)

Silicon Dioxide (SiO2) with iron impurities

Coal (most likely Bituminous or Anthracite)

Bituminous Coal (Grade of Coal), Anthracite (Grade of Coal)

Chert (specifically Jasper or Brown Chert node)

Microcrystalline Quartz (SiO2)

Lapis Lazuli

Lapis lazuli (a rock primarily composed of Lazurite, (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Moonstone (bead form)

Potassium Aluminum Silicate (KAlSi3O8) - a variety of Orthoclase Feldspar

Clear Quartz (Double Terminated)

Silicon Dioxide (SiO2)

Clear/White Quartz (Rock Crystal)

Quartz (Silicon Dioxide, SiO2)

Olivine in Basalt (Peridot)

Magnesium Iron Silicate (Mg, Fe)2SiO4 in Vesicular Basalt

Quartz Crystal (specifically a small Clear Quartz point)

Silicon Dioxide (SiO2)

Smoky Quartz in Matrix

Silicon dioxide (SiO2) within Pegmatite/Gneiss