Igneous, Sedimentary, And Metamorphic Mix

Gneiss (specifically a Granitic Gneiss specimen)

Gneiss (high-grade metamorphic rock primarily composed of Quartz, Feldspar, and Biotite/Amphibole)

Red aventurine

Silicon Dioxide (SiO2) with Hematite/Goethite inclusions

Dalmatian Stone (often called Dalmatian Jasper)

Peralkaline Quartz-Feldspar Rock with Arfvedsonite (formerly believed to be Jasper)

Banded Slate or Siltstone with Quartz/Calcite Veins

Protolith-derived Siltstone or Slate (varies based on degree of metamorphism)

Calcite

Calcium Carbonate (CaCO3)

Orange Calcite

Calcium Carbonate (CaCO3)

Quartz (Iron-Stained)

Silicon Dioxide (SiO2)

Calcite

Calcium Carbonate (CaCO3)

Dalmatian Stone (commonly called Dalmatian Jasper)

Peralkaline Rock (mixed Feldspar, Quartz, and Arfvedsonite)

Greenstone (Epidote/Chlorite-rich Metabasalt)

Greenschist / Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))

Black Star Diopside

Diopside (CaMgSi2O6) with asterism

Tiger's Eye

SiO2 (Silicon Dioxide)

Yellow Quartzite or Yellow Jasper

Quartzite (primarily SiO2 with Iron oxide staining)

Quartzite River Rock

Quartzite (primarily SiO2)

Quartz on Schist

Silicon Dioxide (SiO2) on Foliated Metamorphic Rock

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Metasedimentary or Igneous Matrix

Schist (Micaceous Schist)

Schist (containing mainly Muscovite and Quartz)

Red Jasper

Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2)

Quartz Vein in Host Rock (Likely Slate or Shale)

Hydrothermal Quartz (SiO2) in Pelitic host rock

Petrified Wood

Silicified wood (primarily SiO2 - Silicon Dioxide/Quartz)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Quartzite River Stone

Quartzite (primarily SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Aquamarine

Beryl (Be3Al2Si6O18), specifically the blue-green variety

Diamond Drill Core (Greenschist and Quartzite)

Chlorite Schist / Meta-quartzite (Metamorphic Rock Core Sample)

Tiger Iron / Banded Iron Formation

Banded Iron Formation (SiO2 with Fe2O3 and FeOOH)

Petrified Wood

Silicified wood (primarily SiO2)

Quartzite

Quartzite (consisting primarily of SiO2)

Mica Schist

Mica Schist (primarily Muscovite or Biotite-rich sequence)

Almandine Garnet in Schist Matrix

Almandine - Fe3Al2(SiO4)3

Marble

Recrystallized Calcite (CaCO3)

Green Aventurine

Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)

Citrine Quartz

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Amazonite (Amazon Stone)

Tectosilicate Microcline (KAlSi3O8)

Amethyst

Amethyst (Silicon Dioxide with iron impurities, SiO2)

Amethyst

SiO2 (Silicon Dioxide) - Purple variety of Crystalline Quartz

Quartz Pebble

Silicon Dioxide (SiO2)

Citrine Quartz

Silicon Dioxide (SiO2)

Amethyst

Amethyst (Silicon Dioxide - SiO2 with iron impurities)

Prehnite

Prehnite Ca2Al2Si3O10(OH)2