Unknown (Likely Sedimentary Or Metamorphic)

Banded gneiss cobble

Gneiss, commonly quartz–feldspar–biotite gneiss

Magnetite-rich ironstone (probable magnetite ore)

Magnetite, Fe₃O₄, likely in a fine-grained ironstone matrix

Faceted clear gemstone in a gold-colored ring

Unidentified colorless faceted gem; possibly quartz, glass, or another transparent gem material

Vesicular basalt (lava rock)

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

Pale green translucent mineral fragment

Indeterminate; possibly fluorite, calcite, or glassy quartz

Weathered gray metamorphic rock, likely schist or slate

Foliated silicate rock; possibly mica schist or phyllite

Foliated metamorphic rock (likely mica schist)

Mica schist, probably quartz–muscovite/biotite schist; exact identification requires close inspection

Pyrite-bearing rock, likely pyrite schist or phyllite

Quartz–mica-rich metamorphic rock with disseminated pyrite (FeS₂); exact rock type cannot be confirmed from the image

Likely blue-gray slate

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

Glacially rounded metamorphic boulder

Likely foliated amphibolite or gneiss; exact identification requires a fresh surface and mineral examination

Charoite

Charoite (K(Ca,Na)2Si4O10(OH,F)·H2O)

Pyrite-bearing metamorphic rock (likely pyrite schist or quartz–pyrite ore)

Pyrite (FeS₂) in a quartz–mica-rich matrix; exact host rock is uncertain from the image

Banded gneiss (likely biotite-bearing)

Gneiss; quartz–feldspar–mica assemblage, with possible iron-oxide staining

Tumbled quartz-rich stone, possibly chert or quartzite

Quartzite (mostly SiO₂), though precise identification is uncertain from the image

Baked-clay ceramic fragment (likely brick or pottery)

Fired clay, primarily aluminosilicate minerals; not a natural rock

Weathered granitic rock (likely granite or granodiorite)

Granite–granodiorite; mainly quartz, feldspar, and mica/hornblende

Tumbled quartz-rich stone, likely milky quartz

Quartz (SiO₂), possibly iron-stained milky quartz or quartzite

Dark metamorphic rock, likely schist or slate fragment

Indeterminate; possibly biotite schist, chlorite schist, or slate

Weathered sulfide-bearing metamorphic rock (probable pyrite schist)

Quartz–mica schist with iron sulfides, chiefly pyrite (FeS₂), possibly chalcopyrite (CuFeS₂)

Likely mica schist

Mica-rich schist, probably biotite–quartz–feldspar schist

Weathered quartz-rich metamorphic rock, likely quartzite

Quartzite (mostly microcrystalline quartz, SiO₂), possibly altered sandstone

Exposed aggregate concrete (stone-chip surface)

Portland-cement concrete containing natural aggregate; not a natural rock

Pyrite in a host rock

Pyrite (FeS₂), embedded in a likely sedimentary or metamorphic matrix

Banded gneiss pebble

Gneiss, commonly quartz–feldspar–biotite gneiss

Quartzite river stone

Quartzite (SiO2 silicon dioxide)

Tumbled serpentine

Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and minor carbonate

Jasper

Silicon dioxide (SiO2)

Gneiss Pebble

Gneiss (High-grade metamorphic rock)

Tumbled golden-brown stone, likely sandstone or iron-stained quartzite

Indeterminate from image; probable quartz-rich sandstone (SiO₂) or quartzite

Weathered quartz-rich rock, possibly quartzite or altered granite

Quartz-dominant silicate rock; exact identification requires a fresh surface and tests

Turquoise (Dyed Howlite/Magnesite imitation)

CuAl6(PO4)4(OH)8·4H2O (Target mineral) / MgCO3 (Magnesite substrate)

Likely garnet-bearing metamorphic rock

Garnet schist, possibly garnet-bearing mica schist; garnet is commonly almandine, Fe₃Al₂(SiO₄)₃

Green apatite crystal

Apatite group; likely fluorapatite, Ca₅(PO₄)₃F

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

Quartzite/siliceous schist; chiefly quartz (SiO₂), with probable mica and iron-oxide staining

Weathered iron-rich rock, likely shale or slate

Probably ferruginous shale (iron-oxide-stained mudstone); exact identification requires testing

Red coral beads (possibly dyed or imitation coral)

Corallium spp. skeleton, composed mainly of calcium carbonate (calcite); exact material cannot be confirmed from the image

Blue-green fluorite (rough crystal)

Fluorite, calcium fluoride (CaF₂)

Limonite after Pyrite (Prophecy Stone or Ironstone Concretion)

Goethite/Limonite pseudomorph after Pyrite/Marcasite (FeO(OH)·nH2O)

Foliated metamorphic rock, likely schist or gneiss

Quartz–mica schist/gneiss; exact identification requires close examination of mineral grains

Mica-rich metamorphic rock, likely schist

Muscovite–biotite schist, possibly quartz-bearing

Dark mica-rich metamorphic rock, likely schist

Mica schist, probably biotite–muscovite schist; exact identification requires testing

Milky quartz with iron staining

Quartz (SiO₂)