Mineral, Often A Rock Given Its Aggregate Nature

Blue Apatite

Apatite group (Ca5(PO4)3(F,Cl,OH))

Limestone

Calcium Carbonate (CaCO3)

Chert

Silicon dioxide (SiO2)

Black Sand (Magnetite Sand)

Magnetite-rich Placers (Fe3O4)

Sandstone

Arenite (SiO2 predominantly)

Herkimer Diamond

Quartz (Silicon Dioxide, SiO2)

Red Jasper with Quartz Veining

Jasper (Silicon Dioxide, SiO2) with Quartz (SiO2) inclusions

Quartz Geode

Silicon Dioxide (SiO2)

Granite

Phaneritic Felsic Igneous Rock (composed primarily of Quartz and Alkali Feldspar)

Milky Quartz

Crystalline Silicon Dioxide (SiO2)

Eudialyte in Matrix

Na15Ca6Fe3Zr3Si26O72(OH,Cl,H2O)3

Diorite (River Cobble)

Intermediate plutonic igneous rock

Schist

Mica Schist (Medium-grade metamorphic rock)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Turquoise

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

Sandstone (Greywacke/Siltstone variant)

Clastic Sedimentary Rock (Lithic Wacke)

Granodiorite

Granodiorite (containing Plagioclase, Quartz, and Biotite)

Chevron Amethyst

Silicon Dioxide (SiO2) with iron impurities

Gneiss (with Quartz-Feldspar vein)

Gneiss (high-grade metamorphic rock) containing Quartz (SiO2) and Feldspar (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8)

Sandstone (River Pebble)

Arenite (primarily SiO2)

White Marble

Recrystallized Calcite / Calcium Carbonate (CaCO3)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Basalt

Extrusive mafic igneous rock

Basalt with Quartz/Feldspar Inclusion

Basalt (containing Silicate minerals such as SiO2 and (Ca,Na)(Al,Si)4O8)

Sandstone Concretion

Ferruginous Sandstone Concretion (Primarily SiO2 with Iron Oxide cement)

Sandstone (Weathered)

Arenite (primarily SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Yellow Aventurine (or Citrine-colored Quartz)

Silicon Dioxide (SiO2) with inclusions

Ring with an Orange Inlay

N/A (Man-made object)

Biotite Mica in Host Rock

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

Clear Quartz Crystal (Herkimer Diamond style)

Silicon Dioxide (SiO2)

Basalt

Basalt (Fine-grained extrusive igneous rock)

Sandstone (Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Chalcedony Nodule (Commonly known as Agate or Chert)

Microcrystalline Quartz (SiO2)

Basalt with Plagioclase Phenocrysts (Porphyritic Basalt)

Mafic volcanic rock (formula primarily (Mg, Fe)2SiO4 and CaAl2Si2O8)

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.

Banded Agate

Agate (Cryptocrystalline variety of Quartz, SiO2)

Mica Schist

Crystalline Schist (often containing Muscovite, Biotite, and Quartz)

Sandstone (Quartzose)

Arenite (composed primarily of SiO2)

Dendritic Agate

Dendritic Agate (Silicon Dioxide with Manganese or Iron Oxide inclusions, SiO2)

Granite

Phaneritic Felsic Intrusive Igneous Rock

Granite

Granite (Phaneritic intrusive igneous rock)