Metamorphic (Altered Igneous Rock)

Quartz (Small Fragment)

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Agate

Silicon Dioxide (Chalcedony), SiO2

Epidote

{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)

Banded Gneiss

Gneiss (Metamorphic Rock)

Gneiss (with Quartzite layers)

Gneissic Metamorphic Rock

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic volcanic rock; commonly basalt (plagioclase, pyroxene, and possible olivine)

Quartz

Silicon Dioxide (SiO2)

Biotite-bearing granite or granitic gneiss

Quartz–feldspar–biotite aggregate; likely granite, possibly weathered gneiss

Epidote-bearing basalt

Basalt with epidote-group mineral inclusions, likely epidote or pistachite (Ca₂(Al,Fe³⁺)₃(SiO₄)₃(OH))

Milky quartz with iron-oxide staining and dark matrix

Quartz (SiO₂), likely with hematite/goethite and minor feldspar or mica

Venetian Gold Granite

Phaneritic Felsic Igneous Rock (Granite)

Yellow Quartz

Silicon Dioxide (SiO2)

K2 stone (azurite–granite)

Biotite granite hosting blue azurite (Cu₃(CO₃)₂(OH)₂), often with malachite and quartz

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz with Host Rock Matrix

Silicon Dioxide (SiO2)

Small weathered mineral/rock fragment

Unidentified; likely quartz-rich material, possibly quartzite or feldspar-bearing rock

Weathered iron-rich sandstone or ironstone cobble

Ferruginous sandstone/ironstone, chiefly quartz (SiO₂) cemented or stained by iron oxides and hydroxides

Garnet-bearing metamorphic rock, likely garnet schist or amphibolite

Almandine garnet (Fe₃Al₂Si₃O₁₂) in mica- or amphibole-rich matrix

Quartzite with Mica / Gneiss Pebble

Metamorphic Rock (Quartz-Feldspar-Mica aggregate)

Milky Quartz

Silicon Dioxide (SiO2)

Garnet Gneiss

Garnetiferous Gneiss

Quartz-bearing altered rock, possibly iron-stained quartz vein

Quartz (SiO₂) in a feldspathic/sericitized host, with iron-oxide staining

Ptygmatic Migmatite

Migmatite (consisting of Neosome and Paleosome fractions)

Weathered sandstone or iron-stained sedimentary rock

Likely quartz-rich sandstone; exact identification is uncertain from the photograph

Gneiss

Gneiss (Metamorphic Rock)

Gneiss

Gneissic Metamorphic Rock

Gneiss

Gneissic Metamorphic Rock

Dragon Blood Jasper (also known as Dragon Stone)

Epidotized septarian concretion or Jasper/Epidote breach (typically a combination of Epidote and Pietersite or Red Jasper)

Milky Quartz with Iron Inclusions

Silicon Dioxide (SiO2)

Quartz fragment (Pebble)

Silicon Dioxide (SiO2)

Red jasper (likely polished/chipped fragment)

Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides

Likely weathered fossil shell or fossiliferous limestone

Indeterminate molluscan fossil, possibly a bivalve or brachiopod preserved in carbonate rock

Foliated metamorphic rock, likely gneiss or mica schist

Quartz–feldspar–mica metamorphic rock; exact identification is uncertain from the photograph

Mixed Tumbled Rocks and Minerals Collection

Mixed Minerals and Rocks (Quartz, Feldspar, Jasper, Agate, Lapis Lazuli, Sodalite, Rose Quartz, Fluorite, etc.)

Porphyritic basaltic-andesite

Porphyritic intermediate volcanic rock; chiefly plagioclase and pyroxene/amphibole, with altered mafic minerals and iron oxides

Ironstone / limonite-rich rock

Limonite, chiefly hydrated iron oxides (FeO(OH)·nH₂O), commonly mixed with goethite and hematite

Gneiss

Metamorphic Gneiss

Agate

Silicon Dioxide (Chalcedony), SiO2

Gneiss

Metamorphic rock (Gneiss)

Gneiss

Gneiss (Metamorphic Rock)

Banded Gneiss

Gneiss (Metamorphic Rock)