Not A Rock (Man Made Origin)

Vesicular volcanic rock (likely pumice or scoria)

Vesicular volcanic rock; composition cannot be determined from the image, but likely pumice or scoria

Dark speckled granite pebble

Granite, a quartz–feldspar–mica plutonic rock

Chert (Flint/Jasper variety)

Microcrystalline Quartz (SiO2)

Sandstone Concretion

Sedimentary concretion

Milky quartz

Quartz (silicon dioxide, SiO₂)

Jewelry Chain with Blue and Clear Gemstones (Likely Cubic Zirconia)

Cubic Zirconia (ZrO₂), Silver or White Gold/Platinum Alloy

Quartz-rich metamorphic pebble, likely quartzite

Quartzite, composed predominantly of quartz (SiO₂)

Small quartz-rich pebble

Quartz (SiO₂), possibly quartzite or weathered granite fragment

Likely quartz-bearing rock fragment

Quartz (SiO₂), possibly with calcite or feldspar

Sandstone (Quartzose Pebble)

Arenite (SiO2)

Milky quartz

Quartz (SiO₂), likely massive or vein quartz

River Pebbles (Mixed Lithology)

Conglomerate clasts (Silica-rich and Metamorphic assemblages)

Likely weathered quartz-rich rock fragment

Uncertain; possibly quartz sandstone or a pale feldspathic rock

Quartz-rich rock (possibly quartzite)

Quartzite, composed mainly of quartz (SiO₂)

Fluorite on Matrix

Calcium Fluoride (CaF2)

Rose Quartz

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

Sandstone (likely Quartzite-rich)

Arenite (primarily SiO2)

Basalt (River Stone)

Basalt (composed mostly of plagioclase, pyroxene, and olivine)

Likely garnet-bearing rock (possibly almandine garnet in matrix)

Garnet, likely almandine (Fe₃Al₂Si₃O₁₂); host rock cannot be determined from the image

Chert

Chert (Microcrystalline Quartz)

Possible iron-rich meteorite or metallic sulfide-bearing rock

Unconfirmed; candidates include stony-iron meteorite, iron meteorite, or pyrite-bearing terrestrial rock

Granite

Granite (a plutonic rock)

Basalt

Mafic Igneous Rock (composed primarily of pyroxene and calcium-rich plagioclase)

Limestone

Calcium Carbonate (CaCO3)

Siltstone Pebble

Siltstone (composed of microscopic quartz and clay minerals)

Dark, coarse-grained rock (likely gabbro)

Gabbro, a mafic intrusive igneous rock

Red Aventurine

SiO2 (Silicon Dioxide with Hematite/Goethite inclusions)

Iron-rich rock fragment (likely hematite/goethite-rich ironstone)

Ironstone, composed chiefly of iron oxides/hydroxides such as hematite (Fe₂O₃) and goethite (FeO(OH)); exact identification requires testing

Dark rock specimen (possibly slate or shale)

Unidentified fine-grained rock; slate is foliated metamorphosed shale, while shale is sedimentary mudrock

Weathered quartz-rich rock, possibly quartzite or vein quartz

Quartz-dominant aggregate; chiefly silicon dioxide (SiO₂), possibly quartzite with iron-oxide staining

Greenstone (likely chlorite-rich greenschist)

Greenschist facies metamorphic rock, typically composed of chlorite, actinolite, and albite; exact identification requires testing

Man-made Green Quartz (Lab-grown or Treated)

Silicon Dioxide (SiO2) with artificial coloration

Metallic Ornament / Jewelry

N/A - This is an artificial object, not a geological specimen.

Bornite (“peacock ore”), likely weathered copper sulfide

Bornite, Cu₅FeS₄; possibly chalcopyrite, CuFeS₂, with iridescent tarnish

Granite

Granite (composed primarily of Quartz, Feldspar, and Mica)

Granite

Granite

Greenstone

Metabasalt / Metavolcanic rock

Chert (Flint)

Silicon dioxide (SiO2)

Emerald in Matrix

Beryl (Be3Al2Si6O18)

Goldstone (aventurine glass)

Synthetic copper-bearing soda-lime glass; commonly sold as red goldstone

Weathered iron-stained quartzite or sandstone cobble

Quartzite (quartz-rich rock), possibly ferruginous sandstone

Likely iron meteorite fragment

Iron meteorite, principally kamacite (α-Fe-Ni) with taenite (γ-Fe-Ni)