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

Sandstone (Quartzite-rich Pebble)

Arenite (composed primarily of SiO2)

Lapis Lazuli

Lapis Lazuli (Aggregate primarily of Lazurite: (Na,Ca)8(AlSiO4)6(S,SO4,Cl,1-2) with Calcite and Pyrite)

Chert (Agate/Flint variant)

Microcrystalline Quartz (SiO2)

Caliche (with Lichen Cover)

Calcium carbonate-cemented soil layer (CaCO3)

Yellow Calcite

Calcium Carbonate (CaCO3)

Citrine or Yellow Quartz

Silicon Dioxide (SiO2) with iron impurities

Amethyst Quartz with Matrix

Silicon Dioxide (SiO2)

Citrine

Silicon Dioxide (SiO2) with iron impurities

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Blue Celestite (Celestine) Cluster

Strontium sulfate (SrSO4)

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily SiO2)

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Amethyst Geode

Quartz (SiO₂) with iron impurities

Quartz Geode (with possible Manganese or Goethite coating)

Silicon Dioxide (SiO2)

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with Bioclastic Inclusions

Chert (Arrowhead Fragment)

Chert / Microcrystalline Silicon Dioxide (SiO2)

Fossiliferous Limestone (Bivalve Fossil)

Calcium Carbonate (CaCO3) with Bivalvia fossil

Basalt with Caliche Crust

Aphanitic Mafic Igneous Rock with Calcium Carbonate (CaCO3) coating

Sandstone (likely Fossiliferous Sandstone)

Clastic sedimentary rock (primarily SiO2)

Wishing Stone

Greenschist or Basalt with Quartz/Calcite Vein

Fossiliferous Limestone (Gritstone/Marl)

CaCO3 (Calcium Carbonate) with Fossil Inclusions

Sandstone (Ferruginous)

Arenite with Iron Oxide (Fe2O3) cement

Bay Scallop Shell

Argopecten irradians (Biogenic Calcium Carbonate / CaCO3)

Painted River Pebble (likely Basalt or Greywacke)

Aphanitic Lithic Clast with Anthropogenic Pigment coating

Amethyst

Amethyst (SiO2 with Iron impurities)

Citrine

Citrine (Silicon Dioxide - SiO2)

Epidote

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

Sandstone (Calcareous or Ferruginous)

Clastic sedimentary rock (SiO2 with CaCO3 or Fe2O3 cement)

Bicolor Tanzanite

Zoisite (Ca2Al3(SiO4)3(OH))

Rough Garnet (Almandine)

Almandine Garnet (Fe3Al2(SiO4)3)

Agate

Chalcedony (cryptocrystalline variety of Quartz, SiO2)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Hematite Nodules (Moqui Marbles style)

Iron Oxide (Fe2O3)

Lapis Lazuli

Lapis Lazuli (Complex silicate mineral mix including Lazurite, Pyrite, and Calcite)

Banded Gneiss

Gneiss (complex metamorphic silicate rock)

Chert (Jasper variety)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Quartz (Vein Quartz)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement

Amethyst

Silicon Dioxide (SiO2) with trace Iron (Fe)

Sandstone (likely Greywacke or Siltstone variety)

Arenite / Siltstone (primarily SiO2)

Chert (and Chalcedony/Agate mixture)

Microcrystalline Quartz (SiO2)

Sandstone (Quartz Arenite)

Sandstone (SiO2 with possible mineral cements)