Mineralogical Specimen

Serpentine-rich metamorphic rock

Serpentinite, likely with quartz or calcite veining and minor magnetite

Quartz-bearing rock, possibly weathered granite or pegmatite

Quartz–feldspar–mica aggregate; exact classification is uncertain from the image

Quartz-rich pegmatite (weathered feldspar–quartz rock)

Granitic pegmatite; primarily quartz (SiO₂), feldspar, and minor biotite/iron-oxide minerals

Mica Schist

Mica Schist (primarily Muscovite or Biotite)

Granite

Intrusive igneous rock composed mainly of quartz, alkali feldspar, and plagioclase

Polished porphyritic volcanic rock, likely andesite or basalt

Porphyritic andesite/basalt; commonly plagioclase and pyroxene phenocrysts in a fine volcanic groundmass

Polished septarian nodule

Septarian concretion, commonly calcite/aragonite with brown iron-oxide or siderite veins in a clay-rich matrix

Altered volcanic rock, possibly andesite

Likely porphyritic andesite or dacite with secondary chlorite/epidote and quartz–calcite veins

Hypersthene

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

Iron-rich meteorite candidate

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

Porphyritic polymictic breccia (likely volcanic breccia)

Volcanic breccia; probable polymictic andesite–dacite breccia with quartz/feldspar clasts

Likely serpentinite or serpentinized ultramafic rock

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

Charoite

Charoite (K(Ca,Na)2Si4O10(OH,F)·nH2O)

Granite

Intrusive Phaneritic Felsic Igneous Rock

Dark mafic rock, likely basalt

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

Howlite

Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)

Weathered sedimentary rock, possibly sandstone

Indeterminate clastic sediment; probable quartz-rich sandstone

Red Granite

Phaneritic Plutonic Rock (High Potassium Feldspar)

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

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

Weathered sandstone fragment

Quartz-rich clastic sandstone, possibly arkose or lithic sandstone

Polished brecciated jasper or iron-rich agate

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

Gneiss

Gneiss

Scoria (vesicular volcanic rock)

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

Weathered conglomeratic or breccia cobble

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

Green faceted gemstone, likely emerald

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

Unidentified gray weathered rock

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

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

Small rounded pebble

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

Unidentified rounded mineral/rock fragment

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

Likely weathered basalt or andesite fragment

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

Earthy iron-rich clay or weathered laterite

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

Weathered porphyritic volcanic rock, possibly rhyolite or andesite

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

Weathered iron-rich rock, possibly basalt or ironstone

Indeterminate; likely Fe-oxide-bearing basaltic rock (commonly magnetite/hematite in a silicate matrix)

Dark mafic rock, possibly basalt or altered gabbro

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

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

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

Greenstone (likely altered basalt or serpentinite)

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

Crushed Stone (Gravel/Aggregates)

Crushed rock aggregate (varied composition including Granite, Limestone, and Quartz)

Polished pink gemstone, likely dyed quartz or chalcedony

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

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

Weathered sandstone boulder

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

Iron-stained sandstone

Quartz arenite or lithic sandstone, variably cemented by iron oxides