Metamorphic (Altered Igneous Rock)

Prehnite

Prehnite (Ca2Al(AlSi3O10)(OH)2)

Greenstone (likely serpentinite)

Serpentinite; mainly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chlorite, or other altered minerals

Sodalite

Sodalite: Na8(Al6Si6O24)Cl2

River Pebble (Gneiss or Quartzite mixture)

Metamorphic rock (Commonly Gneissic)

Polished tiger’s-eye jasper (likely brecciated jasper)

Quartz-rich microcrystalline silica, chiefly SiO₂, with iron oxides and possible fibrous pseudomorphs

Iron-rich meteorite candidate

Unclassified stony-iron or iron meteorite candidate; possibly limonite/hematite-bearing terrestrial rock

Quartzite with Feldspar and Mica (Granitic Gneiss Pebble)

Metamorphic Rock / Quartzite / Granitic Gneiss

Limonite/goethite-rich ironstone

Hydrated iron oxides, chiefly goethite (α-FeO(OH)) and limonite (FeO(OH)·nH₂O)

Quartz-rich hydrothermal ore rock, likely gold-bearing quartz vein

Milky quartz (SiO₂) with iron-oxide staining and probable sulfide minerals; host rock may be schist or altered granite

Granite or granitic pebble

Granite; chiefly quartz (SiO₂), feldspar, and mica/amphibole

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Iron-stained quartz-rich rock, possibly goethite-bearing quartz

Quartz (SiO₂) with iron oxides/hydroxides, likely goethite or limonite

White Quartz

Silicon Dioxide (SiO2)

Quartz-rich gravel fragment

Quartz (silicon dioxide, SiO₂), possibly with feldspar or carbonate inclusions

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Lapis Lazuli

A metamorphic rock primarily composed of lazurite (Na,Ca)8[(S,SO4,Cl)2|(Al6Si6O24)], calcite (CaCO3), and pyrite (FeS2).

Orbicular jasper

Silica-rich microcrystalline quartz/chalcedony (SiO₂), commonly with iron oxides and other silicates

Quartz Crystal

Silicon Dioxide (SiO2)

Quartz with Sulfide Inclusions

Silicon Dioxide (SiO2) with metallic mineral inclusions

Soapstone

Steatite (primarily composed of Talc, Mg₃Si₄O₁₀(OH)₂)

Rounded quartz-rich pebble

Likely granitoid-derived quartz–feldspar rock; exact identification uncertain from image

Gneiss Pebble

Gneiss

Tumbled green jasper or serpentine

Likely serpentine-group mineral, chiefly magnesium silicate; possibly epidotized or altered jasper

Lapis Lazuli

Lapis Lazuli (Primary mineral: Lazurite, (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Gneissic Schist

Gneiss-schist (Metamorphic rock)

Gneiss (River Cobble)

Metamorphic Gneiss

Turquoise

Hydrated phosphate of copper and aluminum; CuAl6(PO4)4(OH)8·4H2O

Ruby in Zoisite

Anyolite (Calcium Aluminum Silicate with Aluminum Oxide impurities)

Dark gray fine-grained stone, likely basalt

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

Milky Quartz

Silicon Dioxide (SiO2)

Emerald in Matrix (Quartz/Schist)

Beryl (Be₃Al₂Si₆O₁₈) with Chromium/Vanadium impurities

Serpentine / Antigorite

Mg3Si2O5(OH)4 (Serpentine Group)

Obsidian (likely black obsidian)

Volcanic glass; chiefly silica-rich rhyolitic composition, approximately SiO₂ 70–75%

Educational Geologic Collection

Mixed Mineral and Rock Collection (Various compositions)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Gneiss

Foliated Metamorphic Rock (Gneiss)

Gneiss

Gneiss (High-grade metamorphic rock)