Mineraloid (Human Made Geological Specimen)

Quartz (Small Fragment)

Silicon Dioxide (SiO2)

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Worn quartz-rich pebble, likely chert or quartzite

Microcrystalline quartz (SiO₂), possibly quartzite

Tumbled zebra calcite (likely calcite marble)

Calcite, CaCO₃; commonly recrystallized limestone/marble with dark graphite- or carbon-rich bands

Milky quartz

Quartz (silicon dioxide, SiO₂)

Iron-stained Quartz Pebble

Silicon Dioxide (SiO2) with iron oxide inclusions (Limonite/Goethite)

Quartz (Common or Milky)

Silicon Dioxide (SiO2)

Quartz (Milky Quartz Pebbles)

Silicon Dioxide (SiO2)

Granite

Felsic Plutonic Rock (Granite)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO₂)

Granite

Granite (composed primarily of Quartz SiO2, Potassium Feldspar KAlSi3O8, and Plagioclase Feldspar)

Pyrite-bearing Rock

Iron Sulfide (FeS2) associated with host rock

Petrified Wood

Silicified Wood (SiO2)

Jasper

Silicon Dioxide (Microcrystalline Quartz, SiO2)

Quartz

Silicon Dioxide (SiO2)

Clear Quartz Crystal

Quartz (Silicon Dioxide, SiO2)

Silver (Sterling Silver Jewelry)

Argentum (Ag) mixed with Copper (Cu)

Quartz (Milky/Clear)

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Smoky Quartz

Silicon Dioxide (SiO2)

Fossilized Horn Coral

Order Rugosa (Calcium Carbonate - CaCO3)

Carborundum (Silicon Carbide)

Silicon Carbide (SiC)

Chert (White Chert / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz

Silicon dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Petrified Wood

Silicified wood (primarily Silicon Dioxide, SiO2)

Milky Quartz (with Iron Oxide staining)

Quartz (Silicon Dioxide - SiO2)

Yellow Jasper

Silicon Dioxide (SiO2) with Goethite/Iron oxide inclusions

Sandstone with Iron Concretion

Arenite with Limonite/Goethite Concretion

Quartz

Silicon Dioxide (SiO2)

Quartz on Matrix

Silicon Dioxide (SiO2)

Red Jasper (Amygdaloidal Basalt with Agate)

Silicon dioxide (SiO2) in Basalt host

Small rounded pebble

Indeterminate lithic grain; likely weathered sandstone, iron-stained quartz-rich rock, or a concretion

Jasper Pebble

Microcrystalline Quartz (SiO2)

Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Granite

Phaneritic plutonic rock (approx. 20-60% quartz, 35-90% feldspar)

Petrified Wood

Silicified Wood (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Quartz (specifically a water-worn river pebble)

Silicon Dioxide (SiO2)

Chert (White/Light Tan)

Microcrystalline or Cryptocrystalline Quartz (SiO2)