Mineralogical

Charoite

Charoite (K(Ca,Na)2Si4O10(OH,F)·nH2O)

Hypersthene

Enstatite (Hypersthene variety), (Mg,Fe)SiO3

Weathered iron-rich rock, possibly limonite-bearing sandstone or laterite

Limonite/goethite mixture (hydrated iron oxides), composition uncertain from image

Polished green serpentine

Serpentinite, chiefly antigorite/lizardite Mg₃Si₂O₅(OH)₄

Weathered river pebble, likely quartz-rich sandstone or quartzite

Indeterminate; probable quartz (SiO₂)-rich sandstone/quartzite with iron-oxide staining

Likely serpentinite or serpentinized ultramafic rock

Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with magnetite and minor olivine/pyroxene

Granite

Intrusive Igneous Rock

Weathered conglomeratic or breccia cobble

Lithified polymictic conglomerate/breccia, likely iron-stained siliciclastic rock

Scoria (vesicular volcanic rock)

Scoria; mafic to intermediate vesicular volcanic rock, commonly basaltic or andesitic

Likely serpentine-rich metamorphic rock

Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with magnetite and chlorite

Basalt

Basalt; fine-grained mafic volcanic rock, chiefly plagioclase, pyroxene, and commonly olivine

Weathered sandstone fragment

Quartz-rich clastic sandstone, possibly arkose or lithic sandstone

Weathered iron-rich rock, possibly limonite-bearing sandstone or ironstone

Limonite/goethite-rich ferruginous sandstone; composition uncertain from the photograph

Weathered sedimentary rock, possibly sandstone

Indeterminate clastic sediment; probable quartz-rich sandstone

Weathered iron-rich rock, possibly limonite-bearing sandstone

Limonite/goethite-bearing sandstone or ferruginous conglomeratic rock

Likely weathered basalt or andesite fragment

Fine-grained mafic to intermediate volcanic rock; commonly plagioclase ± pyroxene ± olivine

Iron-rich meteorite candidate

Undetermined stony-iron or iron meteorite; possible weathered iron meteorite

Dark mafic rock, possibly basalt or altered gabbro

Basaltic rock; commonly composed of plagioclase feldspar, pyroxene, and possibly olivine or iron oxides

Weathered sandstone boulder

Sandstone, chiefly quartz (SiO₂) with feldspar and iron-oxide cement

Polished brecciated jasper or iron-rich agate

Microcrystalline quartz (SiO₂), with hematite/goethite and possible iron oxides

Weathered porphyritic volcanic rock, possibly rhyolite or andesite

Altered porphyritic rhyolite–andesite; likely quartz/feldspar phenocrysts in a fine volcanic groundmass

Earthy iron-rich clay or weathered laterite

Hydrated iron oxides and clay minerals, commonly goethite/hematite with kaolinite or illite

Unidentified rounded mineral/rock fragment

Indeterminate; likely a weathered quartz-rich stone or iron-stained granite fragment

Gneiss

Gneiss

Unidentified gray weathered rock

Possibly weathered granite or granitic gneiss; exact identification requires a fresh surface and tests

Polished pink gemstone, likely dyed quartz or chalcedony

Uncertain from image; possibilities include dyed quartz (SiO₂) or chalcedony (microcrystalline SiO₂)

Greenstone (likely altered basalt or serpentinite)

Chlorite–epidote amphibolite/greenschist or serpentinite; exact identification requires testing

Weathered, rounded polymictic pebble (likely volcanic or metamorphic rock)

Indeterminate; possibly altered basalt, greenstone, or epidote-bearing metamorphic rock

Small rounded pebble

Indeterminate lithic grain; likely weathered sandstone, iron-stained quartz-rich rock, or a concretion

Quartz-rich metamorphic rock (probable quartzite)

Quartzite; predominantly crystalline SiO₂, with possible mica and iron-oxide impurities

Weathered mafic rock, likely basalt

Basalt; predominantly plagioclase feldspar and pyroxene, possibly olivine and iron oxides

Small rounded orange-brown stone, likely iron-stained quartzite or sandstone

Indeterminate; probable quartz-rich sandstone/quartzite with iron-oxide staining

Green faceted gemstone, likely emerald

Beryl, Be₃Al₂Si₆O₁₈, colored green by chromium and/or vanadium

Fossilized shell fragment

Bioclastic carbonate, likely a bivalve or brachiopod shell preserved as calcite/aragonite

Likely weathered quartz-bearing rock

Indeterminate; possibly quartz-rich granite or granitic pegmatite

Dark mafic rock, likely basalt

Basalt; predominantly plagioclase feldspar and pyroxene, with possible olivine and iron-titanium oxides

Tumbled purple rock, likely lepidolite-bearing mica schist

Lepidolite-rich mica schist; lepidolite K(Li,Al)₃(Si,Al)₄O₁₀(F,OH)₂, possibly mixed with quartz and feldspar

Chert (Green River Chert)

Microcrystalline Quartz (SiO2)

Onyx (Calcite Onyx / Mexican Onyx)

Calcium Carbonate (CaCO3)

Likely polished leopard-skin jasper or brecciated jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), with iron-oxide and other mineral inclusions; exact variety cannot be confirmed from the image alone

Dendritic Agate (or Dendritic Opal)

SiO2 (for Agate), SiO2·nH2O (for Opal)

Brown agate or chalcedony cabochon pendant

Microcrystalline quartz (SiO₂), likely brown chalcedony/agate