Mineraloid (Human Made Geological Specimen)

Magnetite

Magnetite (Fe3O4)

Man-made Blank Ammunition (Brass)

CuZn (Cartridge Brass - roughly 70% Copper, 30% Zinc)

Sea Glass (White/Clear)

Amorphous Silica (Alkali-Lime-Silica Glass), SiO2 + Na2O + CaO

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Obsidian

Volcanic Glass (Amorphous Silicon Dioxide)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Pyrite (Iron Pyrite)

Iron Sulfide (FeS2)

Milky Quartz (with Iron Oxide staining)

Quartz (Silicon Dioxide - SiO2)

Red Jasper (Banded Jasper)

Silicon Dioxide (SiO2) with Hematite impurities

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Clear Quartz

SiO2 (Silicon Dioxide)

Rose Quartz (Aura Quartz)

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Basalt with Quartz Veining

Basalt (Mafic Extrusive Igneous Rock) with SiO2 (Silicon Dioxide) veins

Greasy Quartz (likely carved Milky Quartz or Aventurine)

Silicon Dioxide (SiO2)

Hematite

Hematite (Fe2O3)

Clear/White Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Oolitic Chert

Ooidal Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (primarily SiO₂ - Silicon Dioxide)

Amazonite

Potassium Aluminum Silicate (KAlSi3O8)

Petrified Wood

Silicified Wood (SiO2)

Quartz (Milky/Chalcedony variety)

Silicon Dioxide (SiO2)

Granite (Micro-specimen)

Plutonic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Opalite (a synthetic glass, often confused with Opal)

Silicon dioxide glass (SiO2nH2O, for natural opal)

Rough Diamond

Pure Carbon (C)

Lepidolite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Petrified Wood

Silicified Wood (primarily SiO2)

Kimberlite

Kimberlite (Porphyritic Peridotite)

Desert Rose

Gypsum (CaSO4·2H2O) or Barite (BaSO4) with Sand inclusions

Pyrite

Iron Sulfide (FeS2)

Quartz pebble with surface markings

Silicon Dioxide (SiO2)

Smoky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Chert (variant Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (River Stone/Pebble)

Chert (SiO2)

Sandstone

Arenite (SiO2 based with quartz grains)

Quartz (Common or Milky Quartz)

Silicon Dioxide (SiO2)

Sandstone (Quartz-rich)

Sandstone (SiO2 dominated)

Obsidian

Volcanic Glass (predominantly SiO2)

Quartz (Chert/Chalcedony Variety)

Silicon Dioxide (SiO2)

Quartz Pebble (with Mica or Iron staining)

Silicon Dioxide (SiO2)

Chert (Nodule)

Microcrystalline Quartz (SiO2)