Synthetic (Not A Rock Or Mineral)

Yellow Agate

Chalcedony (cryptocrystalline silica), SiO2

Quartz with Chalcopyrite and Pyrite

Silicon Dioxide (SiO2) with Copper Iron Sulfide (CuFeS2)

Amethyst Geode

Amethyst (Silicon Dioxide), Formula: SiO2

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Sandstone

Arenite (Siliclastic sedimentary rock)

Schist (Biotite Schist)

Biotite-bearing Schist (K(Mg,Fe)3AlSi3O10(F,OH)2)

Pyrite in Quartz

Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)

Basalt

Mafic volcanic rock (various silicate minerals including Pyroxene and Plagioclase)

Pebble (river rock/beach pebble)

Pebble (clast size class)

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Shale or Siltstone

Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)

Quartz with Mica inclusions (likely Schist or Gneiss host)

Silicon Dioxide (SiO2) with Phyllosilicates (KAl2(AlSi3O10)(OH)2)

Red Jasper

Jasper (Silicon Dioxide, SiO2 with Iron Oxide impurities)

Sandstone (Weathered Pebble)

Arenite (primarily SiO2)

Sandstone (Quartzose Pebble)

Clastic Sedimentary Rock (Litharenite/Quartz arenite)

Unakite

Epidotized Granite

Gneiss

Gneiss (High-grade metamorphic rock)

Basalt with Quartz/Feldspar Vein

Amygdaloidal Basalt with Plutonic intrusion (SiO2/KAlSi3O8)

Quartz Vein in Host Rock (Likely Slate or Shale)

Hydrothermal Quartz (SiO2) in Pelitic host rock

Quartz Geode

Silicon Dioxide (SiO2) within a secondary sedimentary structure

Granite

Phaneritic Plutonic Felsic Rock

Carnelian and White Quartz Bracelet

Silicon Dioxide (SiO2) - specifically Carnelian (Chalcedony) and Rock Crystal/Snow Quartz

Chert (Septarian Concretion/Nodule)

Microcrystalline silica (SiO2) with carbonate mineral veining

Quartz Pebble

Silicon Dioxide (SiO2)

Conglomerate

Conglomerate rock

Schist

Mica Schist

Iron-Stained Quartz (Riverside Cobble)

Silicon Dioxide (SiO2) with Limonite/Hematite inclusions

Lapis Lazuli

Complex mixture of minerals (lazurite, calcite, pyrite, and sodalite); (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Shale or Mudstone (Based on appearance)

Shale (fine-grained, laminated fissile sedimentary rock) / Mudstone (fine-grained, non-fissile sedimentary rock)

Shale

Laminated Mudstone

Tiger's Eye

Pseudomorph of Crocidolite (SiO2 with iron oxides)

Gemstone Sand (Mineral Assortment)

Mixed Mineral Concentrates (Commonly including Quartz SiO2, Garnet X3Y2(SiO4)3, and Tourmaline (Na,Ca)(Li,Mg,Al)3(Al,Fe,Mn)6(BO3)3(Si6O18)(OH,F)4)

Sandstone (with potentially metamorphic or basaltic bands)

Arenite / Lithic Wacke

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily SiO2)

Druzy Quartz Geode (likely Smokey Quartz variety)

Silicon Dioxide (SiO2) - specifically a geode formation lined with druzy quartz crystals, with a likely brownish hue indicating smokey quartz.

Gneiss (Metamorphic Rock)

Gneiss (variable mineral formula primarily containing Quartz, Feldspar, and Mica)

Quartz Pebble

Silicon Dioxide (SiO2)

Sandstone

Arenite (primarily SiO2)

Sandstone (with garnet granules)

Clastic sedimentary rock (primarily SiO2 with Fe3Al2(SiO4)3 inclusions)

Ferruginous Sandstone

Sandstone (rich in iron oxides/hydroxides)