Hematite
Iron(III) oxide (Fe2O3)
mineral
Dalmatian Jasper / Dalmatian Stone
Peralkaline Rock (Silicon Dioxide with Amphibole inclusions)
igneous
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)
metamorphic
Basalt with Caliche
Extrusive Mafic Igneous Rock with Secondary Carbonate Crust
igneous
Granite
Granite
igneous
Quartzite
Quartzite (primarily SiO2)
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Chert (often called Flint or Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Scoria (Lava Rock)
Vesicular Basalt / Scoria
igneous
Sandstone (with potentially metamorphic or basaltic bands)
Arenite / Lithic Wacke
sedimentary
Quartz (Citrine or Smoky variant)
Silicon Dioxide (SiO2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Red Jasper
Silicon dioxide (SiO2) with iron oxide inclusions
mineral
Raw Green Aventurine
Aventurine Quartz (SiO2 + Fuchsite)
metamorphic
Amethyst
Amethyst (Silicon Dioxide, SiO2)
mineral
Quartz (Milk/Citrine variety)
Silicon Dioxide (SiO2)
mineral
Chert (Flint)
Chert (Silicon Dioxide, SiO2)
sedimentary
Amazonite
Amazonite (KAlSi3O8)
mineral
Green Quartzite
Quartzite (primarily SiO2 with trace impurities)
metamorphic
Chert (Jasper variety)
Silicon Dioxide (SiO2)
sedimentary
River Stone (likely Quartzite or Chert)
Recrystallized Silicon Dioxide (SiO2)
metamorphic
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Chert (Green variety)
Chert (Silicon Dioxide, SiO2)
sedimentary
Pink Orthoclase Feldspar with Dendrites
Orthoclase (KAlSi3O8) with Manganese Oxide dendrites
mineral
Iron Slag (Industrial Byproduct)
Anthropogenic Vitrification Product/Ferrous Slag
Mineral-like Industrial Smelting Waste
Quartz (Chert/Chalcedony variety)
Silicon Dioxide (SiO2)
mineral
Sandstone (Quartzite-rich)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
Granite (weathered cobble)
Granite
igneous
Chert (Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Chert (often called Flint for dark varieties)
Chert (SiO2)
sedimentary
Carnelian Agate
Silicon Dioxide (SiO2) with Iron Oxide impurities
mineral
Quartzite
Quartzite (SiO2)
metamorphic
Diorite (River Rock/Cobble)
Intermediate Plutonic Igneous Rock (Diorite)
igneous
Sandstone with Magnetite and Iron Staining
Clastic Sedimentary Rock (contains Fe3O4 and Limonite/Hematite)
sedimentary
Sandstone (Quartzose Sandstone)
Clastic Sedimentary Rock (Lithic arenite / Quartz arenite)
sedimentary
Biotite Schist
Biotite Schist
metamorphic
Basalt
Basalt (Mafic igneous rock)
igneous
Indian Agate
Cryptocrystalline Quartz (SiO2)
mineral
Eudialyte in Matrix
Eudialyte [Na15Ca6(Fe,Mn)3Zr3(Si25O73)(O,OH,H2O)3(Cl,OH)2]
mineral
Indigo Gabbro
Gabbro (Mafic Intrusive Rock)
igneous