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

Milky Quartz/Clear Quartz Cluster

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2) in Geode form

Sandstone (Muddy/Silty Variety)

Arenite with high silt/clay content (clastic sedimentary rock)

Banded Agate

Sedimentary Cryptocrystalline Quartz (SiO2)

Chert (and/or Siltstone River Pebble)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Pebble)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chalcedony Geode

Chalcedony (SiO2) within a geode structure

Chert (specifically as a lithic artifact/projectile point)

Chert (Silicon dioxide, SiO2)

Quartz (Milky and Smoky variety)

Silicon Dioxide (SiO2)

Schist with Schorl (Black Tourmaline)

NaFe3Al6(BO3)3Si6O18(OH)4 (Schorl)

Milky Quartz

Silicon Dioxide (SiO2)

Granite

Granite (phaneritic intrusive igneous rock consisting of quartz, feldspar, and mica)

Fossiliferous Limestone with Rugose Coral

Rugosa (order), typically preserved in CaCO3 (Calcite)

Chalcedony (Botryoidal Agate)

Silicon Dioxide (SiO2)

Rainbow Fluorite

Fluorite (Calcium Fluoride, CaF2)

Chert (Iron-stained)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Agate Geode

Microcrystalline Quartz (SiO2)

Quartz (Milky/Iron-stained)

Silicon Dioxide (SiO2)

Yellow Jasper

Silicon Dioxide with Limonite/Goethite inclusions (SiO2)

Sandstone (specifically an Iron-Concretion)

Arenite with Iron Oxide (Limonite/Goethite) cementation

Chert (Yellow or Tan Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Yellow Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Yellow Chert (Microcrystalline Quartz)

Chert / SiO2 (Silicon Dioxide)

Chert (specifically Flint or Jasper variant)

Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)

Granodiorite Pebble

Granodiorite

Milky Quartz Geode or Druzy Quartz

Silicon Dioxide (SiO2)

Banded Chert (or Banded Jasper)

Silicon Dioxide (SiO2) with Iron Oxide impurities (Hematite/Goethite)

Larimar

Pectolite (Sodium Calcium Silicate Hydroxide) - (NaCa2(Si3O8)(OH))

Chert (Flint)

Microcrystalline Quartz (SiO2)

Sandstone with Foliose Lichen

Arenite (Rock matrix) with Xanthoparmelia or Flavoparmelia (Lichen genus)

Coarse Sand or Fine Gravel

Clastic Sediment (unconsolidated)

Quartzite River Rock

Quartzite (primarily SiO2)

Chert / Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Concretionary Sandstone

Clastic Sedimentary Rock (Sandstone with secondary mineral cementation)

Graywacke

Graywacke Sandstone

Red Sandstone (Hematitic)

Clastic sedimentary rock (SiO2 with Fe2O3 inclusions)

Jasper

Silicon dioxide (SiO2) with iron impurities

Quartz Cluster (Likely Ferruginous)

Silicon Dioxide (SiO2)

Chalky Limestone

Carbonate sedimentary rock (CaCO3)

Chalcedony (Common Agate pebble)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Quartz (Silicon Dioxide, SiO2)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)