Uncertain

Tumbled chalcedony or quartz pebble

Microcrystalline quartz, SiO₂ (likely chalcedony); exact identification is uncertain from the image

Weathered quartz-bearing rock, possibly granite or pegmatite

Likely quartz–feldspar rock; exact mineral identification is uncertain from the photograph

Polished brown agate or jasper

Microcrystalline quartz, SiO₂ (chalcedony variety; exact identification uncertain from image)

Weathered quartz-rich pebble

Likely quartzite or quartz-bearing sandstone; identification is uncertain from the photograph alone

Small faceted dark gemstone, possibly spinel or sapphire

Uncertain; candidates include MgAl₂O₄ spinel or corundum (Al₂O₃) sapphire

Light-colored weathered stone, likely limestone

Calcite-dominated carbonate rock (CaCO₃); exact identification is uncertain from the image

Yellow chalcedony or serpentine-like stone

Likely microcrystalline quartz (SiO₂), possibly yellow jasper; visual identification is uncertain

Weathered mafic rock, likely basalt

Basalt (fine-grained aggregate dominated by plagioclase and pyroxene; identification is visual and uncertain)

Likely schist with quartz-rich fragments

Mica schist, likely biotite schist; exact identification is uncertain from the image

Blue glassy mineral specimen, possibly dyed or synthetic

Uncertain; possible blue fluorite (CaF₂), dyed chalcedony, or man-made glass

Tumbled dark stone, possibly hematite or black jasper

Uncertain; likely hematite (Fe₂O₃) or fine-grained chalcedony/jasper (SiO₂)

Weathered quartz-rich pebble

Likely granitic or quartz-feldspar rock; exact identification is uncertain from the image

Tumbled green glassy mineral, possibly aventurine or fluorite

Uncertain; likely quartz variety (aventurine quartz, SiO₂) or green fluorite (CaF₂)

Dark glassy stone, possibly obsidian

Obsidian (volcanic glass; chiefly SiO₂), though identification is uncertain from the image

Rounded brown pebble

Likely iron-stained quartzite or chert; exact identification is uncertain from the photograph

White calcite fragment (likely limestone or marble)

Calcite, calcium carbonate (CaCO₃); exact host rock is uncertain from the image

Quartz-rich rock, possibly milky quartz or quartzite

Quartz (silicon dioxide, SiO₂); exact specimen identification is uncertain from the image

Blue crystal/mineral specimen (possibly blue quartz or dyed stone)

Uncertain from photograph; possible quartz, SiO₂, or a blue copper-bearing mineral

Polished black limestone or chert pebble

Cryptocrystalline silica (chert) or calcitic limestone; exact identification is uncertain from the photograph

Green tumbled stone, likely serpentine

Serpentine-group mineral, commonly antigorite or lizardite; identification is uncertain from the image

Likely rough metallic meteorite fragment

Unclassified iron or stony-iron meteorite; identification is uncertain from the image alone

Possible basalt or volcanic scoria fragment

Mafic volcanic rock, likely basalt; exact identification is uncertain from the photograph

Weathered metamorphic rock, likely mica schist or gneiss

Quartz–feldspar–mica schist/gneiss; exact identification is uncertain from the photograph

Polished agate or jasper cabochon

Microcrystalline quartz (chalcedony), chiefly SiO₂; exact variety is uncertain from the image

Raw pale-golden mineral aggregate, likely iron-stained quartz or calcite

Uncertain from photograph; possible quartz (SiO₂) or calcite (CaCO₃) with limonite staining

Small rounded mineral pebble, possibly quartz

Uncertain; likely microcrystalline or crystalline SiO₂ (quartz), potentially with iron-oxide staining

Fossil-bearing limestone with ammonite

Calcitic limestone containing an ammonoid fossil (Subclass Ammonoidea; exact genus uncertain)

Tumbled brown stone, possibly jasper or weathered chert

Uncertain; likely microcrystalline quartz (SiO₂), potentially iron-stained jasper/chert

Vesicular basalt (possibly slag-like volcanic rock)

Basalt, predominantly plagioclase–pyroxene–olivine; exact identification is uncertain from the photograph

Weathered granite or granitic gneiss

Granite, chiefly quartz, feldspar, and mica; exact identification is uncertain from the photograph

Green cabochon gemstone, likely glass-filled or synthetic emerald imitation

Uncertain; possible synthetic emerald (beryl, Be₃Al₂Si₆O₁₈) or green glass

Likely tumbled serpentine or greenstone pebble

Serpentine-group minerals, chiefly antigorite/lizardite; identification is uncertain from the photo

Weathered quartz-rich rock, possibly quartzite or chert

Quartz (SiO₂), likely in a quartzite matrix; exact identification is uncertain from the image

Weathered greenish mafic rock fragment

Likely altered basalt or basaltic-andesite; exact identification is uncertain from the photograph

Polished banded gneiss pebble

Gneiss, chiefly quartz–feldspar–mica; exact mineralogy uncertain from image

Weathered quartz-rich pebble

Likely quartzite or granitic/granodioritic rock; exact identification is uncertain from the image

Rounded granitic cobble

Granite, chiefly quartz, feldspar, and mica; exact identification is uncertain from the photograph

Weathered greenish-gray rock fragment

Tentatively basaltic or mafic metamorphic rock; exact identification is uncertain from the photograph

Likely quartz-rich stone, possibly quartzite or milky quartz

Quartz (silicon dioxide, SiO₂); exact rock identification is uncertain from the image

Unidentified small mineral fragment

Possibly quartz or feldspar-bearing rock; exact identification is uncertain from the image

Dark mafic rock, possibly basalt

Basalt (fine-grained mafic silicate rock; identification uncertain from image)

Polished gray metamorphic pebble, likely marble or quartzite

Uncertain; possibly calcitic marble (CaCO₃) or quartzite (SiO₂) with dark mineral veining