Not A Geological Specimen

Mixed tumbled rock and mineral collection

Varied specimens, including probable quartz varieties, jasper, agate, fluorite, rose quartz, amethyst, pyrite, calcite, and others

Flint or chert flake

Microcrystalline quartz (SiO₂), likely fossiliferous or cortex-bearing chert

Assorted gemstone jewelry

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

Mixed rock and mineral specimen collection

Multiple species, likely quartz (SiO₂), calcite (CaCO₃), feldspar, chert, and assorted volcanic/sedimentary rocks

Tumbled aqua glassy mineral specimen, likely chrysocolla or turquoise imitation

Uncertain from image; possible chrysocolla (hydrated copper aluminosilicate, variable composition) or dyed/man-made glass

Fossiliferous limestone

Bioclastic calcarenite/calcirudite, chiefly calcium carbonate (CaCO₃)

Clear quartz sphere or polished quartz cabochon (tentative)

Quartz, silicon dioxide (SiO₂); appearance may also be consistent with ordinary glass, which cannot be ruled out from the image alone

Peridot gemstone pendant

Olivine, gem-quality forsteritic olivine (approximately (Mg,Fe)₂SiO₄)

Light-colored chert or weathered limestone

Microcrystalline quartz (SiO₂) or calcitic limestone (CaCO₃); exact identification requires testing

Carved greenstone figure

Likely nephrite jade (jadeite is a possible alternative), mainly amphibole-group minerals

Faceted glass-like gemstone object

Likely synthetic glass or cubic zirconia; exact material cannot be confirmed from the image

Weathered lateritic ironstone / ferruginous rock

Goethite–hematite-rich laterite, commonly with quartz and clay minerals

Rounded dark gray cobble

Likely basalt or fine-grained mafic volcanic rock; exact identification requires testing

Pale granite pebble (tentative identification)

Granite; a coarse-grained felsic intrusive igneous rock composed primarily of quartz and feldspar, with minor mica or amphibole

Tumbled mixed mineral specimens, likely quartz-rich rocks

Predominantly quartz (SiO₂), with possible jasper, agate, feldspar, and iron-oxide minerals

Iron-rich weathered rock, possibly limonite-bearing sandstone or laterite

Goethite–hematite/limonite assemblage, likely in a ferruginous sandstone or weathered host rock

Likely yellow quartz gemstone ring

Quartz (SiO₂), possibly heat-treated citrine or lemon quartz; metal setting appears to be brass/gold-colored alloy

Black Tourmaline (Schorl)

Schorl (Sodium Iron Aluminum Borosilicate Hydroxide), NaFe2+3Al6(Si6O18)(BO3)3(OH)3OH

Tumbled carnelian (red chalcedony)

Carnelian, a microcrystalline variety of quartz; SiO₂, commonly colored by iron oxides

Unidentified polished mineral fragment

Likely quartz-bearing stone; exact identification is impossible from the blurred photograph

Colorless faceted gemstone (likely glass or cubic zirconia)

Likely cubic zirconia, ZrO₂; exact identification is uncertain from the photograph

Gemstone ring, likely emerald and opal

Green beryl (Be₃Al₂Si₆O₁₈), with probable common opal (hydrated amorphous silica, SiO₂·nH₂O)

Mixed polished river pebbles, predominantly quartzite and quartz

Quartzite (SiO₂), quartz (SiO₂), with possible feldspar-rich and iron-stained lithologies

Carved stone bowl or mortar

Uncertain; likely steatite (soapstone) or fine-grained volcanic stone

Faceted colorless gemstone, likely cubic zirconia or diamond

Most likely synthetic cubic zirconia (ZrO₂); diamond (C) is a less certain alternative

Flint or chert, possibly a knapped stone tool

Microcrystalline quartz (SiO₂), commonly chalcedony with possible carbonaceous impurities

Mixed landscaping gravel and rounded fieldstones

Lithologically mixed aggregate; likely quartzite, basalt, granite, and weathered sedimentary rocks

Cut gemstone ring, likely diamond

Diamond (carbon, C), faceted gemstone; exact stone identification is uncertain from the image

Rounded pink granite pebble

Granite, a coarse-grained felsic intrusive igneous rock composed primarily of quartz, feldspar, and minor mica or amphibole

Likely polished quartz-rich stone or calcite specimen

Uncertain; possibly quartz (SiO₂) or calcite (CaCO₃)

Granite

Phaneritic intrusive igneous rock (primarily SiO2)

Banded Iron Formation (BIF)

Banded Iron Formation

Diamond

Diamond (pure Carbon, C)

Diamond (in a jewelry setting)

Cubic Carbon (C)

Bismuth crystal

Bismuth (Bi), commonly laboratory-grown hopper crystal

Diamond (in jewelry setting)

Adamantine Carbon (C)

Possible weathered basalt or slag fragment

Basalt, chiefly plagioclase and pyroxene; identification is uncertain from the image

Concretion or Geode (unbroken)

Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.

Diamond ring

Diamond (crystalline carbon, C)

Cultured pearls

Pearl; predominantly aragonite (CaCO₃) in nacre with organic conchiolin

Blue Chalcedony and Picture Jasper Beads

Blue Chalcedony (SiO2), Picture Jasper (SiO2)

Diamond (set in Gold)

Diamond (pure carbon, C)