Mixed (Igneous, Sedimentary, Metamorphic, And Minerals)

Exposed aggregate concrete (stone-chip surface)

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

Quartz-rich rock fragment

Unidentified quartz–feldspar-rich rock; exact lithology cannot be determined from the image

Mixed Quartz and Aventurine Chips

Silicon Dioxide (SiO2) with various inclusions

Mixed collection of common river stones

Varied lithologies, visibly including quartz-rich rock, dark mafic rock, sandstone, and purple quartz-bearing material

Chakra Stone (Composite / Man-made Bonded Gemstones)

Composite of Quartz, Lapis Lazuli, Aventurine, Tiger's Eye, and Jasper (SiO2, (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2, etc.)

Mixed rock and mineral specimen collection

Multiple species, likely quartz (SiO₂), calcite (CaCO₃), feldspar, chert, and assorted volcanic/sedimentary rocks

Likely gabbro or diabase

Mafic igneous rock, chiefly plagioclase feldspar and pyroxene; possible olivine and amphibole

Mixed rock and mineral specimen collection

Mostly undetermined from the photograph; apparent quartz-rich rocks, sandstone, granite/gneiss, and possibly iron-oxide-bearing specimens

Polished hematite

Hematite (Fe₂O₃), likely a tumbled iron-oxide specimen

Mixed collection of minerals and rocks (Jasper, Carnelian, Granite, and Quartz)

Silicon Dioxide (SiO2) with varying impurities for silicates and igneous aggregates

Graphite

Graphite (Carbon, C)

Decorative mosaic cross containing mixed rock and glass fragments

Polychrome aggregate; likely quartz, feldspar, marble, granite, and assorted colored glass

Migmatite

Migmatite (Mixed Rock)

Mixed Rock and Mineral Collection

Various geological specimens

Mixed River Pebbles

Clastic Sedimentary Alluvial Deposit / Polymictic Conglomerate Clasts

Mixed Quartz Bracelet (Rose Quartz and Larimar-colored beads)

Silicon Dioxide (SiO2) with various inclusions

General Gravel (River Rock/River Stones)

Mixed Lithic Sediments (Conglomerate Clasts)

Granite (likely a weathered granite cobble)

Granite, a coarse-grained felsic intrusive igneous rock composed chiefly of quartz, feldspar, and mica

Road-surface aggregate (crushed stone)

Unidentifiable mixed lithic aggregate; likely basaltic/andesitic fragments with feldspar, quartz, and weathered rock

Glacial Cobbles (predominantly Granite and Gneiss)

Mixed lithologies (Quartz, Feldspar, Mica assemblage)

Mixed mineral and gemstone specimens

Likely amethyst (quartz), malachite, blue calcite or dyed chalcedony, red jasper, and green aventurine/serpentine

Chakra Stone Bracelet

Mixed Mineral Assembly (Scoria, Amethyst, Lapis Lazuli, Turquoise/Howlite, Impression Jasper, Tiger's Eye, Carnelian, Red Jasper)

Rounded quartz-rich river pebbles

Alluvial gravel; commonly quartzite, chert, and quartz-bearing sandstone fragments

Quartz with Mica inclusions (Pegmatite)

Silicon Dioxide (SiO2) with Muscovite/Biotite inclusions

Epidote in Granite Gneiss

Epidote bearing Orthogneiss (Ca2(Al,Fe)3(SiO4)3(OH))

Graphite

Graphite (Native Carbon, C)

Aventurine (Green Quartz)

Silicon Dioxide (SiO2) with inclusions of Fuchsite (Mica)

Milky Quartz with Nephrite Jade

Silicon Dioxide (SiO2) with Ca2(Mg,Fe)5Si8O22(OH)2

Quartz-bearing rock fragment

Likely milky quartz with iron-oxide staining and possible host-rock minerals; exact identification is uncertain from the image.

Chrysocolla

Hydrated copper phyllosilicate, Cu2-xAlx(H2-xSi2O5)(OH)4·n(H2O)

Stream cobbles and gravel

Unidentified mixed fluvial clasts; likely quartzite, sandstone, and igneous/metamorphic fragments

Tumbled quartz-rich stone, possibly milky quartz or calcite

Quartz (SiO₂) or calcite (CaCO₃); exact identification requires testing

Pegmatite (Granitic Pegmatite with Quartz, Mica, and Tourmaline/Biotite)

Pegmatite

Quartz-rich metamorphic rock, likely mica schist or quartzite

Quartz (SiO₂) with mica, feldspar, and possibly iron-oxide staining

Mixed mineral and rock specimen collection

Assorted silicates, carbonates, oxides, and sulfides; individual species cannot be reliably identified from this image

Mixed Gemstone Collection

SiO2 (Quartz varieties) and Biogenic CaCO3 (Nacre)

Mixed polished rock/mineral specimens

Indeterminate from image; likely quartz-bearing material with iron-oxide staining and possibly mica-rich schist

Decorative polished pebbles

Likely mixed quartz-rich lithologies, including quartzite, jasper, and/or basalt

Epidote in Matrix (likely Amphibolite or Gneiss)

Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH)) in Metamorphic Matrix

Olivine in Quartz/Feldspar Matrix (Peridotite or Granitic Pegmatite)

(Mg,Fe)2SiO4 (Olivine) with Quartz / Feldspar

Concrete or asphalt-like aggregate surface with a dark fragment

Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock

Mixed tumbled gemstone and mineral lot

Primarily quartz varieties (SiO₂), feldspar, beryl/chalcedony, and other unidentified silicate minerals