Sedimentary Rock (Altered)

Dolomite on Prehnite (Saddle-shaped Dolomite)

Dolomite [CaMg(CO3)2] on Prehnite [Ca2Al(AlSi3O10)(OH)2]

Quartzite River Rock (with Limonite staining)

Quartzite (SiO2)

Quartz (Clear / Rock Crystal)

Silicon Dioxide (SiO2)

Red Jasper (Opaque Chalcedony)

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

Graphite

Graphite (Carbon, C)

Red Sandstone

Arenite with Hematite cementation

Red Sandstone

Arenite (with Iron Oxide / Hematite), Formula: SiO2 (Quartz) + Fe2O3 (Hematite coating)

Carnelian

Carnelian (a variety of Chalcedony, SiO₂)

Gneiss (specifically a Granitic Gneiss)

Gneiss (Composition: Quartz, Feldspar, Mica)

Marble

Marble (metamorphosed limestone/dolostone). Predominantly composed of Calcite (CaCO3) for marble derived from limestone, or Dolomite (CaMg(CO3)2) for marble derived from dolostone.

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Red Jasper or Chert

Jasper (SiO2, a variety of chalcedony with iron oxide impurities), Chert (SiO2)

African Turquoise (Jasper)

Polychrome African Jasper (often marketed as 'African Turquoise' due to its color, but it is not true turquoise)

Pyrite

Pyrite (FeS2)

Chert (Iron-Stained)

Microcrystalline Quartz (SiO2)

Laterite (iron-rich nodule, possibly Bauxite as a subtype)

Laterite (composed of various minerals including goethite, hematite, gibbsite, etc.)

River Pebble (likely Quartzite or Chert)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Quartz (SiO₂)

Gneiss

Gneiss (High-grade regional metamorphic rock)

Slate

Foliated Metamorphic Rock (primarily composed of quartz, illite, and chlorite)

Muscovite Mica

Muscovite (Potassium Aluminum Silicate Hydroxide Fluoride), KAl2(AlSi3O10)(OH,F)2

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

River Rock (Basalt/Greywacke)

Aphanitic Basalt or Lithic Sandstone (Greywacke)

Chert (or Flint)

Chert (a cryptocrystalline variety of quartz, SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Jasper

Jasper (a variety of Chalcedony, SiO2)

Leopardskin Jasper

Jasper (a variety of microcrystalline Quartz)

Banded Iron Formation (BIF) with Quartz

Banded Iron Formation, often composed of alternating layers of hematite (Fe2O3) or magnetite (Fe3O4) and chert (microcrystalline quartz, SiO2)

Chert (specifically Yellow/Brown Chert or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

River Pebbles (Tumbled Quartz and Basalt)

Silicon Dioxide (SiO2) for white quartz; Mafic Volcanic Rock for basalt

Fossiliferous Rock (likely Dinosaur Fossil in Matrix)

Permineralized Vertebrate Fossil (Calcium Carbonate/Silica replaced bone material)

Pink Stained Rock (Likely Quartzite or Sandstone with Iron Oxide Staining)

Quartzite (metamorphic) or Sandstone (sedimentary); coloration likely due to hematite or other iron oxides.

Limonite-stained Quartz / Quartzite

Silicon Dioxide (SiO2) with iron hydroxides (FeO(OH)·nH2O)

Quartz Crystal

Quartz (SiO₂)

Puddingstone

Conglomerate (specifically a type of jasper conglomerate or quartz conglomerate)

Chert (Green variety)

Microcrystalline Opaline/Quartz (SiO2)

Slate

Slate (a fine-grained, foliated metamorphic rock). Mineral composition: Primarily composed of mica minerals (muscovite, chlorite, sericite) and quartz, with minor amounts of hematite, pyrite, and other accessory minerals.

Orthoclase Feldspar

Orthoclase (KAlSi3O8)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz / Chert

Silicon Dioxide (SiO2)