Mineraloid (Human Made Geological Specimen)

Basalt

Basalt (Mafic volcanic rock)

Polished basalt with a quartz vein

Basalt, cut by milky quartz (SiO₂)

Milky quartz with iron-stained matrix

Quartz (silicon dioxide, SiO₂)

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Yellow Quartz / Quartzite Pebble

Silicon Dioxide (SiO2)

Amazonite

K(AlSi3O8) - Microcline (Lead-bearing variety)

Pyrite (on host rock/ore)

Iron Sulfide (FeS2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Sunstone

Oligoclase (Plagioclase Feldspar) with inclusions - (Ca, Na)((Al, Si)4O8)

Quartzite (River Stone)

SiO2 (Silicon Dioxide)

Collection of Minerals and Ores

Various (e.g., Uraninite (U3O8), Carbon (C), Native Gold (Au), Hematite (Fe2O3), Galena (PbS), etc.)

Amethyst

Silicon Dioxide (SiO2)

Polished jasper pebble

Jasper, microcrystalline quartz (SiO₂) with iron-oxide and clay-mineral impurities

Black Tourmaline (Schorl)

Schorl (Na(Fe^2+)3Al6(Si6O18)(BO3)3(OH)4)

Carnelian (Carnelian Agate)

Silicon Dioxide (SiO2) - variety of Chalcedony

Possible fossilized ammonite or concretion

Indeterminate fossil specimen; possibly an ammonoid mold/cast in iron-rich sedimentary rock

Mahogany Obsidian

Volcanic glass (SiO2 with Hematite/Magnetite inclusions)

White quartz-rich pebble

Quartz (SiO₂), possibly milky quartz or quartzite

Pyrite (on host rock)

Iron Sulfide (FeS2)

Pyrite (on Quartz matrix)

Iron Sulfide (FeS2)

White Calcite (Dogtooth Spar or Crystalline Calcite)

Calcite (Calcium Carbonate, CaCO3)

Sandstone with Bedding Planes

Arenite (Sedimentary rock composed primarily of sand-sized minerals)

Pink chalcedony (pink agate-like quartz)

Microcrystalline quartz, SiO₂ (chalcedony; likely iron-bearing)

River Pebble (Greywacke or Siltstone)

Clastic Sedimentary Rock

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Basalt

Extrusive mafic rock (Basalt)

Weathered quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), with possible feldspar, mica, and iron-oxide staining

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Quartz Vein on Matrix

Silicon Dioxide (SiO2)

Tumbled black stone, likely basalt

Basalt; fine-grained plagioclase–pyroxene rock, possibly with magnetite

Jasper (specifically a banded or dark variety)

Silicon Dioxide (SiO2) with impurities

Red Sandstone

Clastic Sedimentary Mineraloid (predominantly Quartz grains with Iron Oxide cement)

Petoskey Stone

Hexagonaria percarinata (Fossilized Coral)

Weathered sandstone or siltstone

Clastic sedimentary rock, chiefly quartz and feldspar grains cemented by silica, iron oxides, or carbonate

Quartz Geode

Silicon Dioxide (SiO2) in a Secondary Formation

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Quartz with Pyrite inclusions

Silicon Dioxide (SiO2) with Iron Sulfide (FeS2)

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

Amber

Succinite (Formula: C10H16O)

Tumbled or naturally etched mica-rich mineral specimen, likely muscovite

Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂; possibly phlogopite mica

Weathered quartz-rich rock, likely milky quartz/quartzite

Quartz (SiO₂), possibly quartzite with minor iron-oxide staining

Tumbled purple fluorite (probable)

Fluorite, calcium fluoride (CaF₂)