Mineral With Metamorphic Or Sedimentary Host

Quartz-veined Metamorphic Rock

Quartz Vein in Phyllite or Schist (SiO2 in Silicate Matrix)

Veined Sandstone with Calcite Veins

Sedimentary sandstone with hydrothermal/mineral veins

Quartz Vein in Host Rock

Silicon Dioxide (SiO2)

Likely slate or fine-grained metamorphic stone with quartz vein

Slate–phyllite, composed mainly of quartz, mica, and chlorite; the white vein is likely quartz

Yellow Quartzite (River Pebble)

Metamorphic Quartzite (primarily SiO2)

Quartz Vein in Matrix (Gneiss/Schist)

Silicon Dioxide (SiO2) in Metamorphic Rock Matrix

Likely iron sulfide specimen (pyrite or marcasite)

Pyrite, FeS₂; possibly marcasite, also FeS₂

Dyed Agate

Microcrystalline Quartz (SiO2) with artificial pigment

Veined Pebble (Quartz/Calcite Veined Metamorphic/Sedimentary Rock)

Quartz / Calcite Veined Fault Breccia or Metamorphic Pebble

Milky quartz vein in altered host rock

Quartz (SiO₂), likely with feldspar, mica, and iron-oxide alteration

Serpentinite

Serpentine-group minerals, chiefly antigorite, lizardite, and chrysotile; approximate formula Mg3Si2O5(OH)4

Milky Quartz

Silicon Dioxide (SiO2)

Muscovite Mica

Muscovite / KAl2(AlSi3O10)(OH)2

Agate (or Chalcedony pebble)

Silicon Dioxide (SiO2)

Magnetite / Hematite rich ore

Magnetite (Fe3O4) or Hematite (Fe2O3)

Slate

Slate; predominantly fine-grained mica- and clay-mineral rock, commonly derived from shale

Sandstone Concretion

Sedimentary concretion

Tumbled honey calcite (probable)

Calcite — calcium carbonate, CaCO₃

Milky Quartz

Quartz (Silica / Silicon Dioxide), SiO2

Tumbled green aventurine

Quartz (SiO₂), typically colored by fuchsite mica inclusions

Garnet-bearing rock (likely almandine garnet in a metamorphic matrix)

Almandine garnet, Fe₃Al₂(SiO₄)₃; host rock is uncertain from the image

Quartz Geode or Nodular Quartz

Silicon Dioxide (SiO2) in Host Matrix

Quartz Pebble

Silicon Dioxide (SiO2)

Green Druzy Quartz (Prasiolite)

Silicon Dioxide (SiO2) with inclusions (typically Chlorite or Actinolite)

Emerald

Beryl (Be3Al2(SiO3)6)

Quartz Matrix with Iron Staining / Mica Schist

Silicon Dioxide (SiO2) with Iron Oxide staining

Polished metallic sulfide-bearing pebble

Likely pyrite-bearing slate, schist, or sulfide-rich ore; exact identification requires testing

Iron-rich sulfide ore (likely pyrite-bearing rock)

Likely pyrite (FeS₂) with dark host rock; exact identification is uncertain from the image alone.

Fossil gastropod in granite-like stone

Gastropoda indet.; enclosing rock likely polished granite or gneiss

Veined Quartzite / Vein-filled Sedimentary Rock

Siliciclastic rock with iron oxide-filled fractures

Clear Quartz Cluster

Crystalline Silicon Dioxide (SiO2)

Quartz with Mica/Schist inclusion

Silicon Dioxide (SiO2) with Phyllosilicates

Garnet (likely Almandine or Pyrope)

Garnet (Group Name), Fe3Al2(SiO4)3 or Mg3Al2(SiO4)3

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Quartz vein fragment

Milky quartz (SiO₂), possibly with weathered host rock

Native copper-bearing rock (probable copper ore)

Native copper (Cu), likely with cuprite (Cu₂O), malachite (Cu₂CO₃(OH)₂), and iron-oxide matrix

Quartz with Sulfide Inclusions

Silicon Dioxide (SiO2) with metallic mineral inclusions

Likely magnetite-bearing rock

Magnetite (Fe₃O₄), possibly in a mafic host rock

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Tumbled Black Tourmaline

Schorl (NaFe2+3Al6Si6O18(BO3)3(OH)3OH)

Morganite (Pink Beryl)

Beryllium aluminum silicate Be3Al2(SiO3)6

Turquoise

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