Organic Gemstone (Not A Rock Or Mineral In The Traditional Sense, But Bio Mineralized Material)

Olivine (Peridot)

Magnesium Iron Silicate ((Mg, Fe)2SiO4)

Tiger's Eye

Silicon dioxide (SiO2) with fibrous inclusions of crocidolite

Schist

Mica Schist (Medium-grade metamorphic rock)

Rough Emerald in Matrix

Beryl (Be3Al2Si6O18) with trace Chromium/Vanadium

Fossil Coral

Fossilized Scleractinia or Tabulata (various genera/species)

Amethyst

Amethyst (Silicon Dioxide with iron impurities), SiO2

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)

Granite

Phaneritic Plutonic Igneous Rock (Rich in SiO2)

Amethyst Quartz

Silicon Dioxide (SiO2 with iron impurities)

Chalcedony (Banded/Mottled Variety)

Chalcedony (a cryptocrystalline variety of Quartz, SiO2)

Mica Schist

Mica Schist (Quartz-Biotite-Muscovite Schist)

Amethyst

Silicon Dioxide with Iron impurities (SiO2 + Fe3+)

Sandstone (Water-worn Pebble)

Clastic Sedimentary Rock (primarily SiO2)

Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Red Sandstone

Arenite with Hematite cementation

Rough Diamond

Diamond (Pure Carbon: C)

Amethyst (Chevron or Banded Amethyst)

Silicon Dioxide (SiO2) with iron impurities

Clear Quartz

Silicon Dioxide (SiO2)

Unakite

Epidote-Feldspar rock

Rose Quartz

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

Quartz (Vein Quartz)

Silicon Dioxide (SiO2)

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Quartz (on matrix)

Quartz (Silicon Dioxide, SiO₂)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Carnelian Agate

Silicon Dioxide (SiO2) with iron oxide impurities

Rose Quartz

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

Amethyst

SiO2 (Silicon Dioxide with Iron impurities and natural radiation influence)

Clear Quartz Crystal

Silicon Dioxide (SiO2)

Quartz (Crystalline Cluster)

Silicon Dioxide (SiO2)

Garnet (Almandine)

Almandine, Fe3Al2(SiO4)3

Red Jasper

Jasper (Silicon Dioxide based crypto-crystalline Quartz with Iron inclusions)

Lazulite

Lazulite (Mg,Fe2+)Al2(PO4)2(OH)2

Pyrite

Pyrite (Iron sulfide, FeS₂)

Schist (Garnet-Mica Schist)

Garnet-Mica Schist (X-Y)3Z2(SiO4)3

Ruby (Pink to Red Corundum)

Al2O3 (Corundum with Chromium impurities)

Chrysoprase (Nickel-bearing Chalcedony)

Silicon Dioxide (SiO2) with traces of Hydrous Nickel Silicates

Sapphire (Corundum)

Corundum (Al2O3)

Diorite (Salt and Pepper Rock)

Diorite

Olivine (Peridot)

Magnesium Iron Silicate (Mg,Fe)2SiO4

Red Sandstone

Arenite (predominantly SiO2 with Fe2O3)

Clear Quartz (Rock Crystal)

Quartz (Silicon Dioxide, SiO2)

Muscovite Mica

Muscovite (KAl₂(AlSi₃O₁₀)(F,OH)₂))