Sedimentary Rock (Technically A Microcrystalline Quartz Mineral Aggregate)

Agate (Chalcedony Variation)

Silicon Dioxide (SiO2)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)

Banded Slate or Siltstone with Quartz/Calcite Veins

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

Chert (Basanite variety) with Quartz Vein

Microcrystalline Quartz (SiO2)

Moss Agate

Silicon dioxide (SiO2) with inclusions of hornblende or chlorite

Milky Quartz

Silicon Dioxide (SiO2)

Chert (Common Variety, Jasper)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (White Chert)

Microcrystalline Quartz (SiO2)

Chert (with Limestone matrix)

Microcrystalline Quartz (SiO2)

Chert (Nodule)

Microcrystalline Quartz (SiO2)

Chert (containing Fossil Inclusions)

Microcrystalline Quartz (SiO2)

Chert (Tan/Yellow variety)

Microcrystalline Quartz (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartzite Pebbles (River Stones)

Quartzite (primarily Silicon Dioxide, SiO2)

Quartz Pebble (Chert/Chalcedony)

Silicon Dioxide (SiO2)

Chert (Flint/Jasper variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

Clear Quartz Sphere

Quartz (Silicon Dioxide, SiO2)

Gneiss (High-Grade Metamorphic Rock)

Gneiss (primarily composed of Quartz, Feldspar, and Mica/Amphiboles)

River Cobble (Quartzite-rich Sandstone)

Clastic Sedimentary Rock (Litharenite/Quartzite transition)

Chert (with Limonite staining)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (often called Flint in various colors)

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2) in Host Rock

Sandstone

Sandstone (clastic sedimentary rock, composed predominantly of sand-sized minerals or rock fragments)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert (Common Opal/Jasper variety)

Microcrystalline Quartz (SiO2) with hydration

Conglomerate

Conglomerate (clastic sedimentary rock)

Geode (Chert or Quartz Nodule)

Silicon Dioxide (SiO2)

Yellow Chalcedony (common opal or chert variant)

Silicon Dioxide (SiO2)

Shale or Slate with Quartz Veins

Shale (fine-grained clastic sedimentary rock) or Slate (low-grade metamorphic rock formed from shale) with Quartz (SiO2) veins

Chert (Nodular)

Microcrystalline Silica (SiO2)

Pebble (river rock/beach pebble)

Pebble (clast size class)

Chert (Flint)

Chert (Microcrystalline Quartz, SiO2)

Chert / Flint

Microcrystalline or cryptocrystalline quartz (SiO2)

Rose Quartz

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

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, formula SiO2)

Jasper and Yellow Chert (Tumbled)

Microcrystalline Quartz (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Veined Quartz

SiO2 (Silicon Dioxide)

Chert (Grey Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)