Mineral (Man Made Glass, Not Natural)

Tumbled Green Jasper

Silicon Dioxide (SiO2) with mineral inclusions

Obsidian

Obsidian (volcanic glass; primarily SiO2)

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

Quartz Geode

Silicon Dioxide (SiO2)

Milky Quartz with Matrix

Quartz (Silicon Dioxide, SiO2)

Snowflake Obsidian

Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)

Snowflake Obsidian

Volcanic Glass with Cristobalite inclusions (70–75% SiO2)

Milky Quartz

Silicon dioxide (SiO2)

Milky Quartz with Iron Inclusions

Silicon Dioxide (SiO2)

Dendritic Agate

Silicon Dioxide with Manganese/Iron oxide inclusions (SiO2)

Snowflake Obsidian

Volcanic glass with Spherulite inclusions (SiO2)

Obsidian

Volcanic glass

Potassium Feldspar

Orthoclase (KAlSi3O8)

Quartz in Matrix (possibly Basalt or Siltstone host)

Silicon Dioxide (SiO2) in Host Rock

Milky Quartz Pebble (Tumbled Quartzite)

Silicon Dioxide (SiO2)

Celadonite in Amygdaloidal Basalt

K(Mg,Fe2+)(Fe3+,Al)Si4O10(OH)2 (Celadonite mineral) within a Basalt matrix

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurity)

Pyrite in Matrix (likely Quartz or Schist matrix)

Iron Sulfide (FeS2)

Clear Quartz Point

Silicon Dioxide (SiO2)

Snowflake Obsidian

Volcanic glass containing Spherulitic Cristobalite (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.

Celestite

Celestine (Strontium Sulfate, SrSO4)

Orange Calcite

Calcium Carbonate (CaCO3)

Celestine (or Celestite)

Strontium sulfate (SrSO4)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz with Iron Staining

Silicon Dioxide (SiO2) with Limonite/Hematite inclusions

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

White Quartz Pebble

Silicon Dioxide (SiO2)

Epidosite

Epidosite (Metasomatic rock consisting mainly of Epidote and Quartz)

Quartzite

Quartzite (primarily SiO2)

Milky Quartz (with Iron Oxide staining)

Silicon Dioxide (SiO2)

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

Milky Quartz (among River Rock)

Quartz (Silicon Dioxide, SiO2)

Obsidian

Volcanic Glass (predominantly SiO2)

Mahogany Obsidian

Volcanic Glass (SiO2 + Fe2O3)

Shale

Shale (fine-grained clastic sedimentary rock)

Sandstone

Arenite (composed primarily of SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz Vein on Matrix

Silicon Dioxide (SiO2)

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Milky Quartz with Mineral Inclusions

Quartz (Silicon Dioxide - SiO2)

Chert (specifically Flint or Common Chert)

Chert (Cryptocrystalline Silica, SiO2)