Metamorphic Or Igneous (Context Dependent)

Unknown Rock Fragment

Unknown

Quartz

Quartz (SiO2)

Polished labradorite cabochon

Labradorite, a plagioclase feldspar: (Ca,Na)(Al,Si)₄O₈

Assorted Beach Rocks and Pebbles

Various (Granite, Basalt, Quartz, Conglomerate, etc.)

Greenstone

Greenschist (metamorphosed mafic igneous rock)

Greenish altered rock, possibly serpentinite or chlorite-rich schist

Tentative: serpentine-group minerals, chiefly antigorite/lizardite, or chlorite–actinolite assemblage

Ruby (in costume jewelry context)

Corundum (Al2O3) with Chromium impurities

Bronzite

Enstatite (magnesium iron silicate), (Mg,Fe2+)SiO3

Polished green aventurine (likely)

Quartz, SiO₂, with green mica or other mineral inclusions; the photo alone cannot confirm the exact stone.

Pyrite and Sunstone

Iron Sulfide (FeS2) and Plagioclase Feldspar ((Ca,Na)Al(Al,Si)Si2O8)

Likely tumbled quartz-bearing rock or glittery quartz specimen

Quartz, silicon dioxide (SiO₂), possibly included quartz or quartzite

Mixed rock specimens; likely pink feldspar/quartz and a dark, mica-bearing rock

Tentative visual identification: pink K-feldspar–quartz-rich granite/pegmatite fragments and a dark amphibole- or biotite-rich metamorphic rock; exact identification is uncertain from the image

Greenschist

Chlorite Schist (Greenschist Facies)

Rounded tan pebble, possibly quartzite

Likely quartz-rich quartzite; identification is uncertain from the photo

Likely serpentine pebble

Serpentinite; predominantly serpentine-group minerals, Mg₃Si₂O₅(OH)₄

Quartz (Bull Quartz)

Silicon Dioxide (SiO2)

Tumbled greenstone (likely serpentine or nephrite jade)

Serpentine-group mineral, commonly antigorite [(Mg,Fe)₃Si₂O₅(OH)₄], or nephrite jade (interlocking tremolite–actinolite amphibole)

Granite

Phaneritic Felsic Igneous Rock

Tumbled labradorite bead strand

Labradorite, a plagioclase feldspar; approximately (Ca,Na)(Al,Si)₄O₈

Greenstone

Greenschist (composed of chlorite, actinolite, and epidote)

Granite

Phaneritic plutonic rock (Quartz, Feldspar, Mica)

Goethite pseudomorph after Pyrite

Goethite (FeO(OH)) pseudomorph after Pyrite (FeS2)

Diorite (River Cobble)

Intermediate plutonic igneous rock

Granite

Phaneritic Felsic Igneous Rock

Quartzite Arrowhead

Quartzite (SiO2 silicon dioxide)

Milky Quartz

Silicon Dioxide (SiO2)

Granite

Phaneritic intrusive igneous rock

Rounded greenstone river cobble

Likely serpentinite or chlorite-rich metamorphic rock; exact identification requires testing

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

Granite (Micro-specimen)

Plutonic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Granite Pebble

Granitoid (Felsic Plutonic Rock)

Blue Aventurine

Quartz (SiO2) with inclusions

Gneiss (specifically a water-worn pebble)

Gneiss

Aventurine (Green Aventurine)

Silicon Dioxide with Fuchsite inclusions (SiO2)

Dark weathered igneous rock, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides

Granite Pebble

Granite (Phaneritic intrusive igneous rock)

Note on Image Identification: Textile

N/A (Anthropogenic material)

Blue Obsidian

Obsidian

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Granite

Phaneritic Felsic Igneous Rock

Weathered volcanic rock, likely altered andesite

Altered andesite; predominantly plagioclase and volcanic pyroxene/amphibole, with secondary iron oxides and clay minerals

Brecciated jasper (likely ocean jasper or rhyolitic jasper)

Silica-rich volcanic breccia; predominantly microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and clay/mineral inclusions