Igneous And Metamorphic

Pyrite

Iron Sulfide (FeS2)

Milky Quartz

Silicon Dioxide (SiO2)

Mica

Phlogopite or Biotite group (KMg3(AlSi3O10)(F,OH)2 / K(Mg,Fe)3AlSi3O10(OH)2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Small dark mineral or rock fragment

Undetermined; possibly a dark mafic mineral such as biotite or magnetite

Milky Quartz

Silicon Dioxide (SiO2)

Pegmatite

Pegmatitic Granite containing Quartz, Feldspar, and Schorl

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Likely polished/tumbled dark mineral or glassy rock fragment

Indeterminate from image; possibly hornblende, schorl tourmaline, or obsidian

Pyrite

Iron Sulfide (FeS2)

Likely quartz-bearing rock or mineral fragment

Indeterminate; possibly quartz (SiO₂) with iron-oxide staining and darker matrix

Milky Quartz

Crystalline Quartz (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

White Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Rough Citrine Quartz

Citrine (Silicon Dioxide, SiO2 with iron impurities)

Iron-stained quartz crystal cluster

Quartz (SiO₂), likely iron-oxide-stained; exact variety uncertain

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Milky Quartz

Quartz / Silicon Dioxide (SiO2)

Small pale mineral/rock fragment

Indeterminate; possibly weathered quartz, calcite, or light-colored limestone

Milky and Ferruginous Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Ferruginous Quartz

Quartz (Silicon Dioxide) - SiO2 with Iron Oxide inclusions

Milky Quartz

Silicon dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Pyrite

Iron Sulfide (FeS2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz (with trace inclusions)

Silicon Dioxide (SiO2)

Pink Granite

Phaneritic Granitoid

Likely dark mineral or rock fragment

Indeterminate from image; possibly a dark silicate mineral such as hornblende, biotite, or basalt

Weathered limestone or calcareous tufa

Calcite-rich carbonate rock, primarily CaCO₃ (often micritic limestone or travertine/tufa)

Cloudy Quartz

Quartz (Silicon Dioxide, SiO2)

Biotite in Host Matrix

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

Quartz (Druzy) on Matrix

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz (Smoky Quartz variant)

Silicon Dioxide (SiO2)