Mineral, Specifically A Rock Fragment

Smooth river pebble

Indeterminate lithology; likely fine-grained quartz-rich sandstone, siltstone, or weathered chert

Dalmation Stone (often called Dalmatian Jasper)

Antiperthite-rich Microgranite

Green Aventurine

Quartz (Silicon Dioxide, SiO2) with fuchsite inclusions

Small pale pebble, possibly quartz or feldspar

Unidentified silicate; appearance alone cannot distinguish quartz (SiO₂) from feldspar

Unidentifiable embedded dark fragment

Indeterminate; possibly a dark silicate mineral or lithic inclusion

Baked-clay ceramic fragment (likely brick or pottery)

Fired clay, primarily aluminosilicate minerals; not a natural rock

Blue Lace Agate (Tumbled)

Silicon Dioxide (SiO2) with trace minerals

Quartz-rich rock fragment

Likely granitic or granodioritic rock, composed chiefly of quartz and feldspar with possible mica

Ethiopian Fire Opal

Hydrated Silica (SiO2·nH2O)

Pink Granite

Phaneritic Felsic Igneous Rock

Unidentified small mineral specimen

Indeterminate from the photograph; it may be a light-colored quartz- or feldspar-rich rock with a dark mineral inclusion.

Sardonyx Cameo

Silicon Dioxide (SiO2) - variety Cryptocrystalline Quartz

Satin Spar Selenite

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Moonstone (Green Moonstone / Garnierite)

Potassium Aluminum Silicate (KAlSi3O8) with inclusions of Garnierite

Pink Granite

Phaneritic Felsic Igneous Rock (Granite)

Conglomerate

Clastic Sedimentary Rock

Pink Granite

Phaneritic Felsic Igneous Rock

Clear Quartz Crystal

Quartz (Silicon Dioxide - SiO2)

Small dark mineral/rock fragment

Indeterminate; possibly biotite-rich schist, graphite, or metallic sulfide

Weathered dark mineral/rock fragment

Indeterminate; possibly iron-rich basalt, slag, or a sulfide-bearing mineral

Small brown mineral/rock fragment

Indeterminate; possibly weathered quartz-rich rock, ironstone, or a sulfide mineral

Likely iron-rich rock fragment

Indeterminate; possibly limonite/goethite-stained rock, with no diagnostic features visible

Epidosite (Unakite-related)

Epidosite (composed primarily of Epidote and Quartz)

Milky Quartz

Silicon Dioxide (SiO2)

Small polished stone, possibly a dark agate or jasper pebble

Undetermined; likely microcrystalline quartz (SiO₂)

Granite fragment

Granite; chiefly quartz, alkali feldspar, and plagioclase, with minor mica or amphibole

Green Calcite

Calcium Carbonate (CaCO3)

Weathered golden-brown mineral/rock fragment

Indeterminate from image; possibly iron-stained quartz, feldspar, or a sulfide-bearing rock

Chert

Silicon dioxide (SiO2)

Agate

Silicon Dioxide (SiO2)

Fossil Coral

Hexagonaria (Rugose coral) / Rugosa

Hydrothermal Quartz Breccia

Hydrothermal Breccia with Quartz and Chloritic/Epidote Clasts

Fossiliferous Limestone (Crinoidal Limestone)

Calcium Carbonate with Crinoid Stem Fossils (CaCO3)

Milky Quartz

Quartz (Silica / Silicon Dioxide), SiO2

Emerald

Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities

Pink Granite

Granite (Phaneritic Acidic Igneous Rock)

Uncertain small tan mineral/rock fragment

Indeterminate from image; possibly feldspar-rich rock or calcite

Unidentified small rock or mineral fragment

Indeterminate from the blurred image; possibly quartz-rich stone, feldspar, or weathered concrete-like geological material

Amphibolite (specifically Hornblende Schist/Gneiss)

Amphibole-rich Metamorphic Rock

Blue Quartz (or Blue Aventurine)

Silicon Dioxide (SiO2) with inclusions (typically Crocidolite or Dumortierite)

Pink Granite

Phaneritic Igneous Rock (composed of orthoclase, quartz, and mica)

Weathered rock fragment (likely granite or granitic gneiss)

Undetermined felsic rock; possibly quartz–feldspar granite