Mineraloid Like Synthetic Material

Muscovite Mica

Muscovite - KAl2(AlSi3O10)(OH)2

Chert (Flinty variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (often called Flint)

Chert (Microcrystalline Silicon Dioxide, SiO2)

Rough Quartz (Grey-Green)

Silicon Dioxide (SiO2)

Coquina

Bioclastic Limestone (composed of CaCO3)

Chert (variously identified as Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Yellow Chalcedony (common opal or chert variant)

Silicon Dioxide (SiO2)

Zebra Jasper

Silicon Dioxide (SiO2) with impurities; typically a form of Chalcedony/Microcrystalline Quartz

Chert Pebble / Brachiopod Fossil Internal Mold

Silicon Dioxide (SiO2) / Fossil: Brachiopoda (generic internal mold)

Prase Quartz on Feldspar

Quartz (Silicon Dioxide, SiO2) with Hedenbergite inclusions on Potassium Feldspar (KAlSi3O8)

Sandstone (Water-worn)

Arenite

Tufa

Calcareous Tufa (CaCO3)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2)

Granite

Phaneritic Felsic Igneous Rock (primarily Quartz, Alkali Feldspar, and Plagioclase)

Chert (Flint)

Chert (Cryptocrystalline Quartz, SiO2)

Coquina / Fossiliferous Limestone

Calcite-rich Bioclastic Sedimentary Rock (CaCO3)

Chalcedony (specifically Blue Chalcedony or Common Opal variety)

Silicon Dioxide (SiO₂)

Sandstone

Arenite (primarily SiO2)

Chert

Microcrystalline Quartz (SiO2)

Chert (and Flint)

Silicon Dioxide (SiO2)

Blue Topaz (facetted in jewelry)

Aluminum silicate fluoride hydroxide (Al2SiO4(F,OH)2)

Lepidolite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Granodiorite (containing Biotite and Quartz)

Granodiorite (Plagioclase-rich phaneritic intrusive rock)

Chert (and Limestone)

Silicon Dioxide (SiO2)

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)

Quartz Pebble

Silicon Dioxide (SiO2)

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)

Sandstone

Arenite (composed primarily of SiO2)

Chert (Flint)

Microcrystalline Silica (SiO2)

Banded Chert

Microcrystalline Quartz (SiO2)

Chert (Nodule)

Microcrystalline or Cryptocrystalline Silica (SiO2)

Precious Opal

Hydrated Silica (SiO2·nH2O)

Limonite (Bog Iron)

Limonite (Hydrated iron(III) oxide-hydroxide) - FeO(OH)·nH2O

Chert / Flint

Chert (Cryptocrystalline Quartz, SiO2)

Chert (Quartz Variety)

Silicon Dioxide (SiO2)

Chert (often called Flint in dark varieties)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (Jasper/Flint variety)

Silicon Dioxide (SiO2)

Chert (Iron-stained or Dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (variations include Flint/Jasper)

Chert (SiO2)

Andesite

Andesite (Intermediate Extrusive Volcanic Rock)