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

Banded River Cobble with Mafic Dike

Hydrothermally altered Graywacke or Sandstone with Mafic Intrusion

Limestone

Calcium Carbonate (CaCO3)

Granitic Quartz with Feldspar

Granite (composed primarily of SiO2 and KAlSi3O8)

Quartzite

Quartzite (composed primarily of SiO2)

Quartz Geode Pebble

Silicon Dioxide (SiO2)

Script Jasper

Silicon Dioxide (SiO2) with impurities

Jasper with Hematite inclusions

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3)

Fossilized Coral (Petoskey-like or Favosites)

Anthozoa (Fossilized Coral)

Chert (with Iron Staining)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Orange Calcite

Calcite (Calcium Carbonate, CaCO3)

Druzy Quartz Geode (Vug)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Granite Pebble

Felsic Intrusive Igneous Rock (composed of Quartz, Feldspar, and Mica)

Chert (with Drusy Quartz Pocket)

Silicon Dioxide (SiO2)

Quartz Pebble (River Rock)

Silicon Dioxide (SiO₂)

Red Jasper with Quartz veins

Jasper (Silicon Dioxide, SiO2) with macrocrystalline Quartz veins

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (Jasper/Flint variant)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Blue Chalcedony

Cryptocrystalline Quartz (SiO2)

Ruby (Corundum)

Corundum (Aluminum Oxide with Chromium), Al2O3:Cr

River Cobble (Quartzite-rich Sandstone)

Clastic Sedimentary Rock (Litharenite/Quartzite transition)

Chert (specifically Jasper or Flint variant)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Agate)

Silicon Dioxide (SiO2)

Lepidolite

Lepidolite [K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2]

Granite Pebble

Granite (Phaneritic intrusive igneous rock)

Quartz (vein quartz)

SiO2 (Silicon Dioxide)

Green Chert (Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Limestone

Calcite-rich Sedimentary Rock (CaCO3)

Limonite/Goethite on Shale

Hydrous ferric oxides (FeO(OH)·nH2O) often associated with argillaceous rock

Quartz Geode

Silicon Dioxide (SiO2) in a concretion

Basalt with Quartz/Calcite Vein

Basalt (Mafic Volcanic Rock with secondary mineralization)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Lepidolite on Pegmatite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Chert with Asphaltum (or Tar)

Silica (SiO2) with natural Bitumen/Asphaltum

Chert (Jasper/Chalcedony)

Microcrystalline Quartz (SiO2)

Quartzite River Rock (with Quartz Vein)

Quartzite (SiO2)

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Devil's Toenail (Fossil Oyster)

Gryphaea arcuata (Calcium Carbonate, CaCO3)

Basalt with Quartz/Feldspar Inclusions

Amygdaloidal or Porphyritic Mafic Volcanic Rock with Siliceous Veining

Fluorite

Calcium Fluoride (CaF2)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz (Milky/Yellowish variety)

Silicon Dioxide (SiO2)