Mineral With Metamorphic Or Sedimentary Host

Gneiss with Quartz Veining

Gneiss (High-grade regional metamorphic rock)

Pyritic Gneiss (with Garnet)

Gneiss containing Pyrite (FeS2) and Almandine Garnet (Fe3Al2(SiO4)3)

Agate

Agate (Silicon Dioxide, SiO2)

Small quartz-rich pebble or rock fragment

Quartz (silicon dioxide, SiO₂), possibly with iron-oxide staining or host-rock inclusions

Banded Agate

Silicon dioxide (SiO2)

Banded Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Milky quartz vein rock

Quartz, silicon dioxide (SiO₂), likely massive vein quartz with iron-oxide staining

Blue Apatite

Fluorapatite / Apatite (Ca5(PO4)3(F,Cl,OH))

Black-and-white veined stone, likely marble or calcite-veined metamorphic rock

Probable calcite marble: predominantly recrystallized calcite (CaCO₃) with dark graphite-, mica-, or amphibole-rich minerals

Grey Agate (Tumbled)

Silicon Dioxide (SiO2)

Black Spinel

Magnesium Aluminum Oxide (MgAl2O4)

Shale or slate fragment

Fine-grained phyllosilicate rock, likely slate (metamorphosed shale)

Pyrite-bearing sulfide ore (likely pyrite with iron oxides)

Pyrite, FeS₂, possibly mixed with limonite/goethite and other sulfides

Rough garnet-bearing rock, likely almandine garnet in matrix

Almandine garnet, Fe₃Al₂(SiO₄)₃; exact host rock cannot be determined from the image

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Sedimentary/Metamorphic Matrix

Garnet in Matrix

Almandine or Spessartine Garnet in Quartz/Schist Matrix (X3Al2(SiO4)3)

Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Mica-bearing metamorphic rock, likely schist

Muscovite/biotite mica schist with quartz and feldspar

Quartz vein in iron-stained host rock

Quartz (SiO₂) with limonite/goethite staining, likely in altered basalt or another dark volcanic host

Quartz Pebble

Silicon Dioxide (SiO2)

Iron-stained quartz pebble

Quartz (SiO₂), likely microcrystalline or massive quartz with goethite/limonite staining

Turquoise

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

Garnet Schist

Garnetiferous Micaceous Schist

Pyrite (iron pyrite)

Pyrite, FeS₂

Green calcite (probable)

Calcite, calcium carbonate (CaCO₃)

Druzy Quartz Geode (Vug)

Silicon Dioxide (SiO2)

Veined Grey Metamorphic Pebble

Quartzo-feldspathic vein in Metabasalt / Serpentinite / Slate

Rounded quartz-rich pebble (likely vein quartz or quartzite)

Quartz, silicon dioxide (SiO₂); possibly quartzite if metamorphic

Quartz geode

Quartz (SiO₂), lining a geode cavity; likely with minor iron-oxide staining

Quartz-bearing rock or quartz-rich mineral specimen

Quartz, silicon dioxide (SiO₂); exact host rock is uncertain from the image

Quartz in Greenstone

Metamorphic rock with quartz vein (SiO2 / mixed silicates)

Biotite Mica

Biotite (K(Mg,Fe)3AlSi3O10(OH,F)2)

Sandstone Concretion

Sedimentary Concretion (Quartz sand bound by mineral cement)

Epidote in Matrix

Epidote; Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

Quartz-rich vein rock, likely milky quartz in schist

Milky quartz (SiO₂) with probable mica schist/greenschist host rock

Quartz Veinated Sandstone or Siltstone

Silicon Dioxide (SiO2) within a clastic sedimentary matrix

Likely garnet crystal (rough fragment)

Garnet group; possibly almandine, Fe₃Al₂(SiO₄)₃

Quartz-rich metamorphic rock, likely quartzite or vein quartz

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with mica and feldspar

Quartz with Mica / Chlorite Inclusion

Silicon Dioxide (SiO2) with Phyllosilicate minerals

Schist with Schorl (Black Tourmaline)

NaFe3Al6(BO3)3Si6O18(OH)4 (Schorl)

Emerald in Matrix

Beryl (Be3Al2Si6O18) with Chromium impurities

Pyrite-bearing rock (likely pyrite-rich quartz or schist)

Pyrite, FeS₂, intergrown with quartz and/or mica-rich matrix