The Purple Specimen Is A Mineral (Amethyst); The White Specimen Is A Sedimentary Rock (Limestone Or Marble).

Quartz

Quartz (SiO₂)

Sandstone with trace fossil

Sandstone, possibly with Skolithos or similar trace fossil

Yellow Quartz or Citrine Geode/Cluster

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Citrine (likely Heat-Treated Amethyst)

Silicon Dioxide (SiO2)

Quartz / Clear Quartz

Silicon Dioxide (SiO2)

Charoite

Charoite (Hydrated silicate of potassium, sodium, calcium, barium and strontium): (K,Sr,Ba)(Na,Ca)2[Si4O10](OH,f)·H2O

Red Jasper (Heliotrope family variant)

Silicon Dioxide with Hematite inclusions (SiO2 + Fe2O3)

Amygdaloidal Basalt

Vesicular-Amygdaloidal Basalt (Mafic Extrusive)

Clear Quartz Crystal (Rock Crystal)

Quartz (Silicon Dioxide, SiO2)

Cinnabar in Dolomite or Quartz (Cinnabrite)

Mercury sulfide (HgS) in Dolomite (CaMg(CO3)2)

Chert (Honey Chert or Chalcedony Pebble)

Cryptocrystalline Quartz (SiO2)

Porphyritic Basalt (Chinese Writing Stone or Flower Stone)

Porphyritic Basalt / Porphyry

Asphalt (Bituminous pavement fragment)

Artificial conglomerate / Bitumen-Aggregate mixture

Jasper and Agate (Polished Pebble)

Chalcedony (SiO2 with impurities)

Blue Chalcedony Geode (with Quartz Druzy)

Silicon Dioxide (SiO2) - Microcrystalline variety of Quartz

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Azurite and Malachite on Matrix

Azurite: Cu3(CO3)2(OH)2; Malachite: Cu2CO3(OH)2

Quartz / Vein Quartz

Quartz (Silicon Dioxide, SiO2)

Granite

Phaneritic Igneous Rock (Granite)

Amazonite

Microcline (variety of Feldspar), K(AlSi3O8)

Biotite (Black Mica)

Biotite - K(Mg,Fe)3(AlSi3O10)(OH)2

Chert (with Chalky Cortex)

Silicon Dioxide (SiO2)

Conglomerate with Fossilized Shark Teeth

Clastic sedimentary rock (Conglomerate) containing Elasmobranchii remains

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Jasper / Chert (River Pebble)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Quartz

Silicon Dioxide (SiO2)

Gneiss (specifically a granitic gneiss cobble)

Gneiss (high-grade regional metamorphic rock)

Moonstone

Adularia (Potassium Aluminum Silicate, KAlSi3O8)

Clear Quartz

Silicon Dioxide (SiO2)

Citrine (Heat-treated Amethyst)

Citrine Quartz (SiO2)

Fossiliferous Limestone

Biogenic Calcium Carbonate (CaCO3)

Herkimer Diamond

Quartz (Silicon Dioxide, SiO2)

Pink Granite

Phaneritic Felsic Intrusive Igneous Rock

Yellow Chalcedony (Agate/Jasper mix)

Silicon Dioxide (SiO2)

Chalcedony (Agate)

Silicon Dioxide (SiO2)

Quartzite

Quartzite (primarily Silicon Dioxide, SiO2)

River Siltstone / Mudstone Pebble

Siltstone (composed of mixed silicate and carbonate minerals)

Blue Chalcedony

Chalcedony (SiO2)

Satin Spar (often marketed as Selenite)

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

Quartz (Milky Quartz pebble)

Silicon Dioxide (SiO2)

Limestone

Calcium Carbonate (CaCO3)