All rocks & minerals

Likely slate

Slate, a fine-grained metamorphic rock composed mainly of quartz, mica, and chlorite

Possibly a metallic iron-rich meteorite

Undetermined iron meteorite; composition cannot be confirmed from the image

Likely fluorite-bearing mineral specimen

Fluorite (CaF₂), possibly with associated host rock; identification is uncertain from the dark, blue-lit image

Likely fluorescent calcite-bearing rock

Calcite (CaCO₃), possibly with fluorescent activator impurities; exact identification is uncertain from the image

Veined dark-green pebble (likely serpentinite)

Serpentinite, composed mainly of serpentine-group minerals; pale veins may be calcite or quartz

Pink granite

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

Pink granite

Granite, a coarse-grained felsic intrusive igneous rock; chiefly quartz, potassium feldspar, plagioclase, and minor mica

Small black stone fragment (possibly obsidian)

Unidentified dark rock; obsidian is volcanic glass (composition typically rhyolitic)

Small translucent mineral fragment, possibly quartz

Unidentified; quartz (SiO₂) is one possibility

Unidentified small translucent mineral fragment

Indeterminate from the image; could be quartz (SiO₂) or another pale, translucent mineral

Clear quartz (rock crystal)

Quartz, silicon dioxide (SiO₂)

Clear quartz (rock crystal), possibly a small rough fragment

Quartz, silicon dioxide (SiO₂)

Blue tumbled glass or dyed stone (uncertain)

Unidentified; appearance is consistent with blue glass, but a blue mineral such as dyed quartz cannot be ruled out from the photo

Blue-dyed agate (likely a polished agate cabochon)

Microcrystalline quartz, SiO₂ (chalcedony); likely artificially dyed blue

Possible tumbled carnelian (red-orange chalcedony)

Chalcedony, microcrystalline quartz (SiO₂); identification is tentative from the small image

Tumbled banded stone, likely tiger’s eye

Quartz variety: SiO₂, possibly tiger’s eye; identification is uncertain from the image

Tumbled green stone, likely aventurine

Green aventurine (quartz with fuchsite or other green inclusions), tentatively identified

Likely rough garnet crystals

Possibly almandine garnet, Fe₃Al₂(SiO₄)₃; identification is uncertain from the photograph

Small dark rock fragment (not identifiable from the image)

Undetermined; no diagnostic mineral features are visible

Polished amethyst

Amethyst, purple variety of quartz (SiO₂)

Quartz-rich granite (likely weathered granite)

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

Vesicular basalt (likely weathered lava rock)

Vesicular basalt, chiefly plagioclase and pyroxene with possible olivine; composition cannot be confirmed from the image

Quartz-rich sandstone (possibly quartzite)

Quartz sandstone; if recrystallized, quartzite composed mainly of SiO₂

Mica schist

Mica-rich schist, composed chiefly of muscovite and/or biotite with quartz; exact minerals cannot be confirmed from the image

Mica-rich schist (likely biotite schist)

Mica schist, composed mainly of quartz and mica (biotite and/or muscovite)

Porous limestone

Calcite-rich limestone (predominantly CaCO₃)

Greenstone (likely chlorite-rich metamorphic rock)

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

Serpentinite (likely)

Serpentinite, composed mainly of serpentine-group minerals such as antigorite, lizardite, or chrysotile

Unidentified tan rock fragment

Indeterminate from photograph; possibly a carbonate rock such as limestone

Granite

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

Mica-rich schist (likely biotite schist)

Mica schist; chiefly quartz and mica, commonly biotite ± muscovite

Biotite-rich schist (probable)

Mica schist, likely biotite–quartz–feldspar schist

Fossiliferous limestone with a fossil shell

Calcite-rich limestone (CaCO₃), containing a likely brachiopod or bivalve fossil

Veined limestone (likely marbleized limestone)

Calcite-rich carbonate rock, chiefly calcite (CaCO₃); exact identification requires testing

Sandstone

Quartz-rich sandstone (composition cannot be confirmed from the image)

White pebble, likely milky quartz

Quartz (SiO₂), probable; identification is uncertain from the image alone

White pebble, likely milky quartz

Probably quartz (SiO₂); identification is uncertain from the image alone.

Greenstone pebble (likely serpentine-rich)

Serpentinite or chlorite-rich metamorphic rock; exact identification is uncertain from the photograph

Small rounded pebble, likely quartz-rich stone

Unidentifiable from the image; possibly quartzite or quartz-bearing river pebble

Milky quartz

Quartz (silicon dioxide, SiO₂)

White sea glass (naturally frosted glass fragment)

Man-made silicate glass, typically soda-lime glass; not a mineral or rock

Milky Quartz

Silicon dioxide (SiO2)