Mixed (Igneous, Sedimentary, Metamorphic, And Minerals)

Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Weathered quartzite cobble

Quartzite, predominantly crystalline SiO₂

Quartz vein in host rock

Quartz (SiO₂), likely milky quartz; host rock is uncertain from the photo

Polished labradorite-bearing rock

Labradorite, a calcium-rich plagioclase feldspar; likely mixed with quartz and mafic minerals

Weathered polymictic conglomerate or breccia

Polymictic conglomerate/breccia, likely iron-stained and quartz-bearing

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

Pegmatite with Quartz and Feldspar

Intrusive Igneous Rock

Yellow Calcite

Calcite (Calcium Carbonate, CaCO3)

Clear Quartz (Rock Crystal) Bracelet

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Clear Quartz Crystal

Silicon Dioxide (SiO2)

Magnetite (Iron Ore)

Iron(II,III) oxide (Fe3O4)

Gneiss

Gneiss (High-grade metamorphic rock)

Pink Granite

Phaneritic Plutonic Felsic Igneous Rock (Granite)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Mixed Quartz and River Pebbles (Stone Collection)

Mixed assortment containing mainly Silicon Dioxide (SiO2)

Mixed stream gravel and common rock specimens

Predominantly quartz-rich granitoid, quartzite, sandstone, shale/slate, and mafic volcanic fragments; exact species cannot be determined confidently from the image

Bauxite

Bauxite (Al(OH)3 mixed with Fe2O3 and clay minerals)

Assorted gemstone jewelry

Mixed natural and synthetic gemstone cabochons and faceted stones; individual species cannot be determined reliably from this image

Mixed mineral and rock specimens

Undetermined assortment; individual pieces may include quartz, feldspar, mica, and other common minerals

Mixed mineral and shell specimen assortment

Primarily unidentified quartz-/feldspar-like pebbles with possible dark basalt or iron-rich fragments; white pieces may include shell or calcite

Black Tourmaline

Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Tumbled yellow-brown quartzite or jasper

Quartzite, predominantly microcrystalline quartz (SiO₂), possibly iron-stained jasper

Yellow chalcedony or quartz fragment

Microcrystalline quartz, SiO₂ (tentative; possibly iron-stained chalcedony)

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Unakite (likely)

Epidote–pink feldspar–quartz rock; commonly termed unakite

Faceted gemstones, likely mixed small sapphires or spinel

Corundum (Al₂O₃) or spinel (MgAl₂O₄); exact identification requires testing

Quartz

Silicon dioxide (SiO2)

Quartz (Milky or Yellow/Citrine Quartz)

Silicon Dioxide (SiO2)

Likely quartz-rich rock fragment

Quartz (SiO₂), possibly iron-stained or mixed with feldspar

Blue apatite (likely dyed or enhanced)

Apatite group; fluorapatite, Ca5(PO4)3F, is the common blue variety

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz (Pebble)

Silicon Dioxide (SiO2)

Gneiss

Gneiss

Red Agate Sphere (or Banded Jasper/Agate)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Quartz pebble

Silicon dioxide (SiO2)

Granite (Pink/Potassium Feldspar Granite)

Felsic Plutonic Rock (Potassium Feldspar, Quartz, Mica, and Amphibole)

Magnetite

Magnetite (Fe3O4)

Quartz (Orange/Pink variety)

Silicon Dioxide (SiO2)

Quartz Crystal

Silicon Dioxide (SiO2)