Mineral (Sedimentary Context)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Greenstone (Celadonite-bearing Volcanic)

Hydrothermally altered basalt or andesite with Celadonite (K(Mg,Fe2+)(Fe3+,Al)Si4O10(OH)2)

Amethyst (Tumbled/Weathered Quartz)

Amethyst (SiO2 with iron impurities)

Black Onyx

Black Chalcedony (SiO2)

Green Chalcedony (Batu Akik)

Silicon Dioxide (SiO2)

Granite

Granite (phaneritic intrusive felsic igneous rock)

Ferruginous Conglomerate

Ferruginous Conglomerate (Clastic Sedimentary Rock)

Schist (Biotite/Mica Schist)

Medium-grade regional metamorphic rock (rich in Phyllosilicates)

Gold (Elemental Metal)

Gold (Au)

Chert (often called Flint in this context)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Ruby (in costume jewelry context)

Corundum (Al2O3) with Chromium impurities

Greenstone

Greenschist (composed of chlorite, actinolite, and epidote)

Fuchsite

K(Al,Cr)2(AlSi3O10)(OH)2 (Chromium-rich Muscovite)

Chert (Flint)

Silicon Dioxide (SiO2)

Iron Slag

Anthropogenic Vitreous Silicate (Byproduct of Smelting)

Ferruginous Quartzite (also known as Ironstone or Gossan)

Ferruginous Quartzite with Goethite/Hematite staining

Green Quartzite (Aventurine-like)

Quartzite (primarily SiO2 with chromium-rich mica or chlorite inclusions)

Serpentinite

Serpentinite (containing minerals of the Serpentine subgroup: Antigorite, Lizardite, and Chrysotile; formula (Mg,Fe)3Si2O5(OH)4)

Seraphinite

Clinochlore (Mg,Fe)5Al(AlSi3O10)(OH)8 - specific variety for Seraphinite due to its fibrous inclusions and chatoyancy.

Chert (often called Flint in this context)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Opalite

Synthetic Glass, SiO2 base with metallic inclusions

Shale or Slate with Quartz Veins

Shale (fine-grained clastic sedimentary rock) or Slate (low-grade metamorphic rock formed from shale) with Quartz (SiO2) veins

Slag

Anthropogenic Vitrophyre (Iron or Smelting Slag)

Dark weathered igneous rock, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides

Arsenopyrite in Quartz Matrix

Arsenopyrite (FeAsS) with Quartz (SiO2)

Weathered iron-rich rock, likely basalt or ironstone

Probable weathered basalt (mafic silicate rock); exact identification requires a fresh surface and testing

Chert (Jasper or Flint variant)

Chert (composed of microcrystalline quartz, SiO2)

Granite

Granite (a common type of Felsic Intrusive Igneous Rock)

Fluorite (often referred to casually as 'Fluorspar' in industrial contexts)

Fluorite (CaF2)

Onyx Marble (also commonly called Onyx)

Calcite (CaCO3), often with other mineral impurities

Quartz (Druzy) in host rock

SiO₂ (Silicon Dioxide) as Quartz, with unspecified host rock components (likely silicates and iron oxides)

Quartz (possibly milky quartz)

Quartz (Silica; SiO₂)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Sedimentary/Metamorphic Matrix

Chert (often called Flint in archaeological contexts)

Microcrystalline or cryptocrystalline Silica (SiO2)

Sandstone with trace fossil

Sandstone, possibly with Skolithos or similar trace fossil

Chert (often called Flint in archaeological contexts)

Silicon Dioxide (SiO2)

Quartz

Quartz (SiO2 - Silicon Dioxide)

Tiger's Eye (often misinterpreted as Gold Ore in this context)

Pseudomorph of Quartz after Crocidolite (SiO2)

Gneiss

Gneiss (pronounced 'nice')

Rutilated Quartz

Quartz (SiO2) with Rutile (TiO2) inclusions

Petrified Wood

Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)