Mineraloid (Human Made Geological Specimen)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz Crystal (specifically a small Clear Quartz point)

Silicon Dioxide (SiO2)

Asphalt (Bituminous Concrete)

Composite material (bitumen binder with mineral aggregate)

Crinoid and Coral Fossils in Limestone

Fossiliferous Limestone with Rugosa (order) and Crinoidea (class)

Transit Token (RTD Denver)

Nickel-plated brass or bronze alloy (Cu-Sn-Zn-Ni)

Baroque Pearl (and potentially a small Sapphire/Blue Topaz)

Pearl: Calcium Carbonate (aragonite or calcite) with conchiolin. Sapphire: Aluminum Oxide (Al2O3). Blue Topaz: Al2SiO4(F,OH)2.

Quartz

Silicon dioxide (SiO2)

Plagioclase Feldspar

NaAlSi3O8 – CaAlSi2O8 (Sodium-Calcium Aluminum Silicates)

Placer Gold Nugget

Native Gold (Au)

Smoky Quartz and Feldspar Pegmatite

Granitic Pegmatite (chiefly SiO2 and KAlSi3O8)

Moss Agate

Cryptocrystalline Quartz (SiO2 with Manganese or Iron Oxide inclusions)

Milky Quartz (Water-worn Pebble)

Quartz (Silicon Dioxide) - SiO2

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Sunstone (Feldspar variety)

Oligoclase or Andesine (Na,Ca)(Al,Si)4O8

Carnelian (a variety of Chalcedony)

SiO2 (Silicon Dioxide) primarily colored by iron oxide (Hematite)

Quartz (Iron-Stained)

Silicon Dioxide (SiO2)

Quartz (Milky/Crystal Variety)

Silicon Dioxide (SiO2)

Pyrite with Limonite/Goethite Alteration (Pseudomorph)

Iron Sulfide (FeS2) transitioning to Hydrated Iron Oxides (FeO(OH)·nH2O)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartzite

Quartzite (SiO2)

Milky Quartz Pebble

Silicon dioxide (SiO2)

Yellow Jasper

Silicon Dioxide (SiO2) with iron hydroxides (Goethite)

Faceted Glass (Costume Jewelry)

Amorphous Silicon Dioxide with colorants (Glass)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Clear Quartz

Silicon dioxide (SiO2)

Rose Quartz

Crystalline Silicon Dioxide with trace Titanium/Manganese/Iron (SiO2)

Ferruginous Quartz

Quartz (Silicon Dioxide, SiO2) with iron oxide inclusions

River Pebble (Brecciated Chert/Siltstone)

Silicon Dioxide (SiO2) with mineral inclusions

Banded Agate (Tumbled)

Silicon Dioxide (SiO2) - variety of Chalcedony

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Sandstone Pebble (Quartzite-rich)

Clastic Terrigenous Sedimentary Rock (SiO2 dominant)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide inclusions (Hematite/Goethite)

Milky Quartz Mushroom Carving

Quartz (Silicon Dioxide, SiO2)

Optical Calcite (Iceland Spar)

Calcium Carbonate (CaCO3)

Quartz (Milky or Clear variety)

Silicon Dioxide (SiO2)

Yellow Chalcedony

Chalcedony (a cryptocrystalline variety of Quartz, SiO₂)

River Rocks (Basalt and Sedimentary Stones)

Mafic Igneous Rock (Basalt) and Clastic Sedimentary Rock

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Veined Quartz

SiO2 (Silicon Dioxide)

Petrified Wood (Silicified Wood)

Silicified Wood (primarily Chalcedony/Quartz, SiO2)