All rocks & minerals

Gneiss

Quartz–feldspar–biotite gneiss

Likely graywacke (feldspathic sandstone)

Lithified sandstone, likely a feldspathic or lithic wacke; exact identification requires closer examination

Likely mica schist

Mica-rich schist, likely muscovite–biotite schist; exact identification requires examination

Weathered dark shale or slate-like rock

Fine-grained argillaceous rock; exact identification requires examination of a fresh surface

Likely biotite-rich schist

Mica schist, composed chiefly of quartz and biotite mica

Druzy quartz cluster on matrix

Quartz (SiO₂), likely a drusy coating on a carbonate or other rock matrix

Pumice (likely)

Vesicular volcanic rock, typically rhyolitic to dacitic glass with minor feldspar and other minerals

Tiger’s-eye ring

Tiger’s-eye, a quartz-rich pseudomorph of fibrous crocidolite; SiO₂

Petrified wood

Silicified fossil wood; commonly composed of microcrystalline quartz (SiO₂) replacing the original wood

Petrified wood

Silicified fossil wood; commonly composed of microcrystalline quartz (SiO₂)

Green beryl (likely aquamarine)

Beryl, Be₃Al₂Si₆O₁₈; blue-green varieties are called aquamarine

Iron-stained milky quartz

Quartz (SiO₂), colored by iron-oxide/hydroxide staining

Banded sandstone

Quartz-rich sandstone, likely with iron-oxide staining

Snowflake obsidian

Volcanic glass (predominantly SiO₂) with spherulitic cristobalite or feldspar inclusions

Orange stilbite (zeolite)

Stilbite-Ca, approximately NaCa₄(Si₂₇Al₉)O₇₂·28H₂O

Green fluorite (probable)

Fluorite, CaF₂

Tumbled green aventurine

Quartz (SiO₂), commonly with green fuchsite mica inclusions

Two small opaque mineral fragments, likely red jasper and blue-gray sodalite

Red jasper: microcrystalline quartz (SiO₂); possible sodalite: Na₈(Al₆Si₆O₂₄)Cl₂

Black stone, possibly obsidian or basalt

Undetermined from image; possible volcanic glass (obsidian, SiO₂-rich) or basalt (fine-grained mafic rock)

Tumbled rose quartz

Quartz, SiO₂ (pink variety known as rose quartz)

Green aventurine (likely), shaped star

Quartz, SiO₂, with green fuchsite inclusions

Likely turquoise-colored mineral or dyed stone

Unidentified opaque blue-green material; turquoise, chrysocolla, dyed howlite, or glass cannot be distinguished from the image alone

Rose quartz

Quartz (SiO₂), pink variety; trigonal crystal system

Tumbled red jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored red by iron oxides

Amethyst-bearing quartz

Quartz, SiO₂; purple color is commonly caused by trace iron and natural irradiation

Amethyst-bearing quartz

Quartz (SiO₂), purple variety amethyst; possibly attached to pale quartz or host rock

Milky quartz crystal

Quartz (SiO₂), likely a naturally terminated crystal

Tumbled amethyst

Quartz, SiO₂; purple variety colored mainly by iron impurities and natural irradiation

Likely synthetic ruby (corundum)

Corundum (Al₂O₃), probably laboratory-grown

Tumbled green aventurine (likely)

Quartz, SiO₂, with green fuchsite inclusions

Pink-red faceted gemstone ring (likely garnet)

Possibly pyrope–almandine garnet, (Mg,Fe)₃Al₂(SiO₄)₃; identification from the image is uncertain

Gemstone cocktail ring, likely jade and orange chalcedony

Green jade (jadeite, NaAlSi₂O₆, or nephrite, Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂) with orange chalcedony (microcrystalline SiO₂); identification is visual

Orange tumbled feldspar, likely sunstone

Probably potassium feldspar (orthoclase or microcline); identification is uncertain from the image

Dark green, fine-grained pebble (likely amphibolite or greenstone)

Likely amphibolite, composed mainly of hornblende and plagioclase; exact identification requires examination

Weathered limestone pebble

Calcite-rich limestone, chiefly calcium carbonate (CaCO₃)

Milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Tumbled hematite

Hematite (α-Fe₂O₃)

Likely slate

Slate, a fine-grained metamorphic rock composed mainly of quartz, mica (sericite/muscovite), and chlorite

Porphyritic basalt (likely porphyritic andesite)

Plagioclase-phyric volcanic rock; plagioclase phenocrysts in a dark, fine-grained groundmass

Vesicular basalt (lava rock)

Basalt, a mafic volcanic rock composed mainly of plagioclase feldspar and pyroxene, commonly with olivine

Granite (likely)

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

Granite (likely biotite-bearing granite)

Granite, composed mainly of quartz, feldspar, and mica (likely biotite)