Not A Rock Or Mineral

Pink Granite

Phaneritic Felsic Intrusive Igneous Rock

Iolite-bearing Gneiss (Cordierite)

Cordierite (Mg2Al4Si5O18) in Gneiss matrix

Fluorite (likely Green Fluorite variant)

Calcium Fluoride (CaF2)

Sodalite Syenite

Sodalite-bearing Syenite (Na8(Al6Si6O24)Cl2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Banded Chalcedony (Agate)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Dyed Purple Agate

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Turquoise

CuAl6(PO4)4(OH)8·4H2O (Hydrated copper and aluminum phosphate)

Banded Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Fossilized Crinoid Stem

Class Crinoidea (Echinodermata)

Petoskey Stone (Petrified Favosites)

Favosites (extinct colonial coral), CaCO3 with Silica replacement

Carnelian

Carnelian (Silicon Dioxide - SiO2)

Smoky Quartz

Silicon Dioxide (SiO2)

Carnelian

Carnelian (a variety of Chalcedony); SiO2 (Silicon Dioxide)

Druzy Quartz

Quartz (Silicon Dioxide, SiO2)

Banded Agate (specifically Eye Agate / Chalcedony)

Agate (Cryptocrystalline variety of Quartz, SiO2)

Carnelian

Carnelian Chalcedony (SiO2 with Iron Oxide impurities)

Gneiss

Gneiss (High-grade Metamorphic Rock)

Jasper

Silicon dioxide (SiO2) with iron impurities

Carnelian (Agate)

SiO2 (Silicon Dioxide with Iron Oxide impurities)

Green Agate

Silicon Dioxide (SiO2) - Chalcedony variety

Carnelian

Carnelian (a variety of Chalcedony, SiO2)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Sandstone (Wonderstone)

Silicified Sandstone / Orthoquartzite with Liesegang rings

Lapis Lazuli

Lapis Lazuli (A metamorphic rock primarily composed of Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2, along with Calcite and Pyrite)

Granitoid (Granite/Gneiss)

Granitoid silicate rock, primarily quartz and feldspar

Basalt

Basalt (Aphanitic mafic volcanic rock)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Quartz (Milky/Yellowish variety)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, formula: SiO2)

Basalt

Basalt (Aphanitic Mafic Igneous Rock)

Pink Granite

Phaneritic Plutonic Igneous Rock (high K-feldspar)

Siltstone with Quartz Vein

Siltstone (primarily SiO2, Al2O3, Fe2O3)

Vesicular Basalt with Oxidation

Scoriaceous Olivine Basalt (Mafic volcanic rock)

Chert (White-Tan variety)

Silicon dioxide (SiO2) / Microcrystalline Quartz

Ironstone Concretion

Siderite or Limonite Concretion

Agate (Moss or Plume Agate variety)

Silicon Dioxide (SiO2)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)

Ruby in Kyanite

Al2O3 (Corundum) in Al2SiO5 (Kyanite-Fuchsite-Quartz)

Quartz (likely Rose Quartz or Milky Quartz based on color)

Quartz (SiO2 - Silicon Dioxide)