Synthetic (Man Made Glass)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Quartz with Mica inclusions (likely Iron-stained)

Silicon Dioxide (SiO2) with Phyllosilicates

industrial byproduct (anthropogenic rock-like material)

Slag Glass

Amorphous Silica / Glass Slag

Snowflake Obsidian

Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)

mineraloid / anthropogenic

Slag (Industrial Glass Slag)

Amorphous Silica / Ferro-silicate Slag

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

Green Aventurine

Aventurine Quartz (SiO2) with Fuchsite inclusions

metamorphic

Quartz (Milky or Citrine-tinted)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz Crystal with Inclusions

Silicon Dioxide (SiO2)

Muscovite (Mica) in Quartz Matrix

Muscovite (KAl2(AlSi3O10)(OH)2) and Quartz (SiO2)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Citrine

Citrine (Silicon Dioxide - SiO2)

Quartz in Matrix (possibly with Biotite or Hornblende)

Quartz (Silicon Dioxide, SiO2) in Granitic Matrix

Quartz (specifically Milky or Clear Quartz fragment)

Silicon Dioxide (SiO2)

Quartz (Smoky/Grey variety)

Silicon Dioxide (SiO2)

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2 + K(Al,Cr)2AlSi3O10(OH)2

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Obsidian

Volcanic Glass (70-75% SiO2)

Quartz

Silicon Dioxide (SiO2)

Snowflake Obsidian

Volcanic glass containing Spherulite inclusions (primarily Cristobalite, SiO2)

Chert / Red Jasper

Microcrystalline Quartz (SiO2)

Quartz

Silicon Dioxide (SiO2)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Amethyst (Rose-tinted variation)

Silicon Dioxide (SiO2) with trace iron impurities

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Smoky Quartz

Silicon Dioxide (SiO2)

Chert (variations include Flint or Jasper)

Silicon Dioxide (SiO2)

Quartz (Milky/Smoky variety on matrix)

Silicon Dioxide (SiO2)

Amethyst (Chevron Amethyst/Dream Amethyst)

Silicon Dioxide (SiO2) with trace Iron impurities

Muscovite Mica

Muscovite (Potassium Aluminum Silicate) - KAl2(AlSi3O10)(F,OH)2

Milky Quartz with Limonite

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide)

Igneous

Milky Quartz/Clear Quartz Cluster

Silicon Dioxide (SiO2)

Smoky Quartz (Vein Quartz)

Quartz (Silicon Dioxide, SiO2)

Quartz (specifically Clear Quartz or Rock Crystal)

Silicon Dioxide (SiO2)