Uncertain

Gypsum (selenite)

Gypsum, CaSO₄·2H₂O; likely a translucent, bladed selenite crystal

Banded sedimentary concretion

Likely a carbonate (calcite-rich) concretion with concentric mineral bands; exact composition cannot be confirmed from the image

Druzy quartz on a yellow-brown host, likely agate or chalcedony

Quartz, SiO₂; microscopic drusy quartz crystals coating chalcedony

Milky quartz

Quartz (silicon dioxide, SiO₂)

Clear quartz (likely)

Quartz, SiO₂

Banded agate (likely carnelian/chalcedony)

Microcrystalline quartz (SiO₂), chalcedony; banded variety

Tumbled jasper (likely)

Microcrystalline quartz, SiO₂; likely jasper, a variety of chalcedony

Likely granite

Granite, a coarse-grained felsic intrusive igneous rock

Tumbled jasper or chert pebble

Microcrystalline quartz, mainly SiO₂, likely jasper/chert

Tumbled green aventurine (probable)

Quartzite dominated by quartz (SiO₂), with green fuchsite mica or chlorite inclusions

Diamond jewelry pendant or cluster

Diamond, crystalline carbon (C), likely mounted in metal

Polished yellow jasper or iron-rich chert

Microcrystalline quartz (SiO₂) with iron-oxide inclusions

Polished jasper or chert

Microcrystalline quartz (SiO₂), likely iron-stained jasper/chalcedony

Blue quartzite or blue schist (likely quartzite)

Quartz-rich metamorphic rock; predominantly SiO₂, possibly with blue amphibole or dumortierite

Native gold nugget or flake

Native gold (Au), possibly with minor silver/electrum

Fossil coral fragment

Fossilized colonial coral, commonly *Hexagonaria* (often called Petoskey stone) or related scleractinian/tabulate coral

Weathered granitic pegmatite (uncertain)

Felsic granitoid/pegmatitic rock, chiefly quartz and feldspar with dark biotite or amphibole

Uncertain translucent mineral specimen, possibly calcite

Calcite (calcium carbonate, CaCO₃), tentative identification

Uncertain small polished gemstone or mineral

Indeterminate; likely quartz-family material, possibly druzy quartz or glass-like chalcedony

Uncertain polished mineral specimen

Indeterminate; possibly quartz or feldspar with iron-oxide staining

Uncertain fine-grained rock or mineral-bearing specimen

Indeterminate; possible quartz- or feldspar-bearing matrix with reflective grains

Uncertain—likely weathered granite or quartz-rich rock

Granite (quartz–feldspar–mica aggregate), tentative

Uncertain polymict breccia or altered volcanic rock

Likely hydrothermally altered volcanic breccia; exact mineral identification requires testing

Quartz-rich stone tool or shaped mineral specimen

Likely milky quartz or quartzite (SiO₂); exact material cannot be confirmed from the image

Tumbled blue-green stone, likely amazonite

Amazonite, a green microcline feldspar (KAlSi₃O₈)

Tumbled green stone, likely serpentine

Serpentine-group minerals, commonly antigorite or lizardite; approximate formula Mg₃Si₂O₅(OH)₄

Tumbled black stone, likely black obsidian

Obsidian (volcanic glass; chiefly silica-rich rhyolitic composition)

Tumbled yellow-green stone, likely serpentine or nephrite jade

Serpentine-group mineral, commonly antigorite/lizardite; possible nephrite, a tremolite–actinolite amphibole aggregate

Large rounded boulder, likely foliated metamorphic rock (possibly gneiss or schist)

Undetermined foliated silicate rock; mineral species cannot be confirmed from the photograph

Amethyst (purple quartz crystal cluster)

Quartz, SiO₂; amethyst is purple, iron-bearing quartz

Quartz-rich rock, likely milky quartz with iron staining

Quartz (SiO₂), possibly a quartz vein fragment

Raw milky quartz (likely quartz/chalcedony fragment)

Quartz, silicon dioxide (SiO₂)

Blue aventurine or dyed blue quartz

Quartz, SiO₂; likely aventurine quartz if natural blue inclusions are present

Likely quartz-rich metamorphic rock (quartzite or micaceous schist)

Quartzite/schist; predominantly quartz (SiO₂) with mica and minor iron oxides

Hematite bead bracelet

Hematite (iron(III) oxide, Fe₂O₃), likely polished magnetic hematite or hematite-coated beads

Tumbled ruby-bearing corundum

Corundum (Al₂O₃), likely ruby variety

Calcite crystal fragment

Calcite (calcium carbonate, CaCO₃)

Coarse-grained granite or granitic gneiss

Granite; mainly quartz, feldspar, and mica (possibly foliated orthogneiss)

Polished yellow-brown chalcedony (likely carnelian or mossy/iron-stained agate)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide inclusions

Likely weathered granite or granitic gneiss

Granite; mainly quartz, feldspar, and minor mica/amphibole

Small pink quartz pebble

Quartz, SiO₂; possibly rose quartz or pale chalcedony

Fossilized bone fragment (tentative)

Petrified bone; mineral replacement commonly by microcrystalline quartz, calcite, or iron oxides