Mineral, Often Found As Detrital Grains In Sedimentary Rocks

Quartz Geode in Chert/Limestone Matrix

Silicon Dioxide (SiO2) within Sedimentary Host Rock

Carnelian

Carnelian (a variety of Chalcedony, SiO2)

Limonite (Iron Ore)

Hydrous Iron Oxide (goethite, lepidocrocite)

Pink Quartzite

Quartzite (SiO2 with iron oxide impurities)

Rough Sapphire

Corundum (Al2O3)

Magnetite

Magnetite (Fe3O4)

Petrified Wood

Silicified wood (Quartz/Chalcedony - SiO2)

Quartzite

Quartzite (primarily SiO2)

Granite (specifically the Ubatuba variety)

Phaneritic Igneous Rock (Granodiorite/Monzogranite)

Siltstone with Quartz Vein

Siltstone (primarily SiO2, Al2O3, Fe2O3)

Mica Schist

Mica Schist (primarily Muscovite and Biotite phyllosilicates)

Limestone

Calcium Carbonate (CaCO3)

Yellow Jade (Yellow Chalcedony/Quartz)

Silicon Dioxide (SiO2)

Basalt Water-Worn Pebble

Aphanitic Mafic Igneous Rock

Fossiliferous Limestone

Calcium Carbonate (CaCO3) with fossil inclusions

Quartzite Pebble

Quartzite (predominantly Silicon Dioxide - SiO2)

Mica Schist

Mica Schist (primarily Muscovite or Biotite KAl2(AlSi3O10)(OH)2)

Bauxite / Iron-rich Laterite

Laterite (principally Al(OH)3, Fe2O3, and SiO2)

Granite

Granite (a plutonic igneous rock composed primarily of quartz and feldspar)

Grey Agate

Silicon Dioxide (SiO2) - Variety of Chalcedony

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

Quartzite

Quartzite (composed primarily of SiO2)

Yellow Agate

Chalcedony (cryptocrystalline Quartz), SiO2

Ruby

Corundum (Al2O3 with Chromium traces)

Epidote

Epidote - {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)

Banded Slate or Siltstone with Quartz/Calcite Veins

Protolith-derived Siltstone or Slate (varies based on degree of metamorphism)

Red Jasper (Jasper)

Silicon Dioxide (SiO₂)

Blue Sapphire (Tumbled/Polished)

Corundum (Al2O3)

Celestite (Celestine)

Celestine (Strontium Sulfate, SrSO4)

Chert (Yellow Jasper/Flint)

Silicon Dioxide (SiO2)

Quartz Geode

Quartz (Silicon Dioxide - SiO2) within a Chalcedony and Limonite shell

Quartzite

Quartzite (primarily SiO2)

Red Quartzite

Quartzite (SiO2)

Quartzite

Quartzite (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Quartzite

Quartzite (primarily SiO2)

Yellow Chalcedony (Carnelian/Yellow Agate)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Ferruginous Sandstone (with possible trace fossils)

Arenite with Iron-Oxide Cement (SiO2 with Fe2O3)

Yellow Quartzite (Beach Pebble)

Quartzite (primarily SiO2)

Oolitic Limestone

Oolitic Limestone (Calcium Carbonate, CaCO3)

Diorite

Diorite (Intermediate intrusive igneous rock)

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)