All rocks & minerals

Blue opalescent glass-like gemstone (possibly imitation opalite)

Likely man-made opalite glass; composition varies, typically silica-based glass

Polished dark stone sphere, likely black obsidian

Obsidian (natural volcanic glass; composition varies, commonly rhyolitic)

Tumbled labradorite (probable)

Labradorite, a plagioclase feldspar; approximate formula (Ca,Na)(Al,Si)₄O₈

Polished labradorite sphere

Labradorite, a plagioclase feldspar ((Ca,Na)(Al,Si)₄O₈)

Rainbow fluorite crystal

Fluorite (calcium fluoride, CaF₂)

Likely tumbled moonstone

Feldspar, probably orthoclase or plagioclase; composition varies

Possibly polished black tourmaline (small cut stone)

Tourmaline-group mineral, likely schorl; complex borosilicate, approximately NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Pale green tumbled stone, possibly green calcite

Uncertain from the image; appearance is consistent with calcite (CaCO₃)

Likely raw amethyst with a tumbled pale-green stone

Amethyst: purple quartz (SiO₂); green specimen is uncertain, possibly fluorite or green quartz

Tiger’s-eye (likely cabochon gemstone)

Quartz variety, chiefly SiO₂, with fibrous crocidolite-derived inclusions

Likely weathered river pebble

Unidentified rounded lithic pebble; the image does not show enough detail to determine its rock species

Tumbled carnelian

Carnelian, a red-orange variety of chalcedony (microcrystalline quartz, SiO₂)

Weathered iron-rich rock, possibly laterite or ironstone

Indeterminate ferruginous rock; likely iron-oxide-cemented material (goethite/limonite ± hematite)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Milky quartz (likely)

Quartz, silicon dioxide (SiO₂)

Milky quartz (rough fragment)

Quartz, silicon dioxide (SiO₂)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Likely rose quartz

Quartz (SiO₂), commonly called rose quartz

Polished agate (likely blue-gray chalcedony)

Microcrystalline quartz, SiO₂; chalcedony, possibly banded agate

Amethyst

Quartz, SiO₂; purple coloration is associated with trace iron and natural irradiation.

Tumbled hematite

Hematite (α-Fe₂O₃), iron oxide

Possibly tumbled dark stone

Undetermined; appearance alone is insufficient for identification

Dark gray fine-grained rock fragment

Possibly andesite or basalt; exact identification is not possible from the image alone

Pink feldspar (likely orthoclase)

Orthoclase, KAlSi₃O₈

Possible blue topaz or glassy blue mineral fragment

Indeterminate from image; possibly topaz (Al₂SiO₄(F,OH)₂)

Greenstone (likely chlorite-rich schist)

Greenschist; commonly composed of chlorite, actinolite, epidote, and albite

Small pale green crystal, likely beryl (aquamarine)

Possibly beryl, Be₃Al₂Si₆O₁₈; identification is uncertain from the image

Pink faceted gemstone, possibly tourmaline

Unidentified faceted mineral; pink tourmaline (elbaite, Na(Li₁.₅Al₁.₅)Al₆(Si₆O₁₈)(BO₃)₃(OH)₄) is one possibility

Blue topaz (possible)

Topaz, Al₂SiO₄(F,OH)₂

Possible blue sapphire

Corundum (Al₂O₃), possibly blue sapphire

Mixed polished stone and mineral collection

Several small, tumbled specimens; individual species cannot be identified reliably from the image

Small polished pink-and-white pebble, possibly quartz or feldspar

Undetermined; likely a quartz- or feldspar-rich silicate

Rainbow-coated amethyst (likely treated quartz)

Quartz, SiO₂; purple color from iron-related defects. The iridescent surface appears artificially coated, often with a titanium-based film.

Black tourmaline (schorl) in matrix

Schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Granite

Granite, a coarse-grained felsic intrusive igneous rock composed chiefly of quartz, feldspar, and mica

Likely mica-rich schist

Mica schist, probably muscovite- and/or biotite-bearing; exact identification requires closer examination

Fossil-bearing rock, possibly a fossiliferous sandstone or limestone

Unidentified sedimentary matrix with fossil impressions; exact fossil and rock cannot be determined from the image

Weathered porphyritic volcanic rock, possibly andesite

Porphyritic andesite (tentative; exact identification requires testing)

Tumbled red granite

Granite, chiefly quartz, feldspar, and mica

Likely rough garnet-bearing rock

Possibly garnetiferous schist or gneiss; identification is uncertain from the photo

Likely quartz-rich metamorphic pebble

Possibly quartzite; exact identification is uncertain from the photo

Small water-worn pebble, likely quartz-rich stone

Unidentified quartz-rich lithic pebble; precise identification is not possible from the image