Sedimentary Rock (Specifically A Concretion Or Possibly A Geode)

Ferruginous Sandstone (Gritstone)

Arenite with Iron-Oxide Cement (SiO2 with Fe2O3 and FeO(OH))

Iridescent Ammonite

Ammonoidea (Species: likely Cleoniceras or Desmoceras); Mineral: Aragonite/Ammolite (CaCO3)

Jet

Lignite (Anthracite-grade compact coal)

Quartz on Basalt

Silicon Dioxide (SiO2) on Mafic Igneous Rock

Pink Granite

Phaneritic Felsic Intrusive Igneous Rock

Chert (Smoky variety)

Microcrystalline Quartz (SiO2)

Amethyst (Quartz)

SiO2 (Silicon Dioxide)

Moqui Marble

Iron Oxide Concretion (Limonite/Hematite shell with Sandstone core)

Moqui Marble (Shaman Stone)

Iron Oxide Concretion (Hematite/Goethite shell with Sandstone core)

Calcite

Calcite (CaCO3)

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Quartz (Milky/Common)

Quartz (Silicon Dioxide, SiO2)

Pink Granite (River Pebble)

Phaneritic Felsic Igneous Rock

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Chert (Nodule)

Microcrystalline quartz (SiO2)

Chert / Jasper

Microcrystalline Quartz (SiO2)

Blue Calcite

Calcium Carbonate (CaCO3)

Blue Apatite

Apatite group (Ca5(PO4)3(F,Cl,OH))

Chert (Nodule)

Microcrystalline Quartz (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Ironstone Concretion (Limonite/Hematite Nodules)

Ironstone (principally Limonite FeO(OH)·nH2O or Hematite Fe2O3 mixed with silica/clay)

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Chalcedony

Chalcedony (a microcrystalline variety of Quartz, SiO2)

Chalcedony with Matrix

Silicon Dioxide (SiO2)

Flint (Chert)

Cryptocrystalline Quartz (SiO2)

Druzy Quartz

Quartz (Silicon Dioxide, SiO2)

Drupa Quartz (Sparkly Drusy Quartz on Matrix)

Crystalline Silicon Dioxide (SiO2) on host rock

Amethyst (Raw Quartz)

Silicon Dioxide (SiO2) with iron impurities

Celestine (or Celestite)

Celestine (Strontium Sulfate, SrSO4)

Limestone

Calcium Carbonate (CaCO3)

Granite (with Orthoclase and Quartz)

Phaneritic Felsic Igneous Rock (KAlSi3O8 + SiO2)

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Pink Granite (Water-worn Cobble)

Phaneritic Felsic Intrusive Igneous Rock

Pink Granite

Phaneritic intrusive felsic igneous rock

Mixed collection of minerals and rocks (Jasper, Carnelian, Granite, and Quartz)

Silicon Dioxide (SiO2) with varying impurities for silicates and igneous aggregates

Scoria

Extrusive Basaltic Scoria

Chrome Diopside

Magnesium Calcium Silicate (MgCaSi2O6) containing Chromium impurities

Limestone

CaCO3 (principally composed of Calcite)

Amethyst Quartz

Amethyst (SiO2 with Iron impurities)

White Quartz (Milky Quartz)

Silicon Dioxide (SiO2)