Sedimentary (Primary) With Artificial Modification

Dyed Agate

Agate (Silicon Dioxide, SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Dyed Blue Agate Slice

Silicon Dioxide (Chalcedony variety), $SiO_2$

Dyed Agate Geode Slice

Silicon Dioxide (SiO2) - Banded Chalcedony

Obsidian (likely snowflake-free black volcanic glass)

Volcanic glass; predominantly rhyolitic silica melt (SiO₂-rich, noncrystalline)

Dyed or color-enhanced agate/microcrystalline quartz bead

Chalcedony (microcrystalline SiO₂), likely agate

Smoky Quartz

Silicon dioxide (SiO2)

Dyed Crackle Quartz

Silicon Dioxide (SiO2) with artificial dye

Smoky Quartz

Silicon Dioxide (SiO2) with natural radiation treatment

Dyed Quartzite

Metamorphosed Quartz (SiO2) with synthetic pigment

Peridot

Olivine ((Mg, Fe)2SiO4)

Silicon Carbide (Carborundum)

Moissanite (SiC), though mostly synthetic

Red Tiger's Eye

SiO2 (Silicon Dioxide) - Pseudomorph of Quartz after Crocidolite

Tumbled yellow calcite

Calcite (CaCO₃), likely honey/yellow calcite

Carnelian (a variety of Chalcedony)

Cryptocrystalline Quartz (SiO2) with iron oxide inclusions

Likely black beach pebble

Undetermined; possibly basalt, chert, or dark slate

Blue Lace Agate

Silicon Dioxide (SiO2) - Variety of Chalcedony

Dyed Blue Agate

Chalcedony (Silicon Dioxide / SiO2)

Blue Quartzite (Dyed Quartzite)

Silicon Dioxide (SiO2) with dye

Dyed Agate (Tumbled)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Dyed Quartz Pendant

Silicon Dioxide (SiO2) with artificial dye

Blue Banded Agate (Dyed)

Silicon Dioxide (SiO2) - Chalcedony variety

Iron Slag

Anthropogenic Vitreous Silicate (Byproduct of Smelting)

Dyed Agate

Silicon Dioxide (SiO2) with synthetic dyes

Dyed Purple Agate

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Dyed Blue Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Banded Agate (Dyed Purple)

Agate (Variety of Chalcedony/Quartz), SiO2

Blue-dyed howlite beads (likely)

Howlite, Ca₂B₅SiO₉(OH)₅, commonly dyed blue to imitate turquoise

Aura Quartz Geode (Angel Aura Quartz)

Silicon Dioxide (SiO2) bonded with precious metals

Druzy chalcedony pendant, likely coated or dyed

Microcrystalline quartz (SiO₂), chalcedony with druzy quartz; surface may have titanium or metallic coating

Uncertain fine-grained rock or mineral-bearing specimen

Indeterminate; possible quartz- or feldspar-bearing matrix with reflective grains

Dyed Agate / Quartz

Silicon Dioxide (SiO2) with artificial dye

Dyed Agate

SiO2

Dyed Pink Quartzite

Tumbled and Dyed Quartzite (SiO2 with dye treatment)

Cobalt Blue Slag Glass

Amorphous Silicon Dioxide (anthropogenic) with Cobalt additives

Copper Ore (Malachite and Limonite bearing)

Cuprite, Malachite, and Limonite mixture

Smoky Quartz

Silicon Dioxide (SiO2)

Smoky Quartz

Silicon Dioxide (SiO2)

Dyed Agate / Quartz (Tumbled)

Silicon Dioxide (SiO2) with artificial dye

Dragon Vein Agate (Dyed/Fractured Quartz)

Silicon dioxide (SiO2)

Dyed Agate Geode

Silicon Dioxide (SiO2) with artificial pigment

Blue Dyed Quartzite

Silicon Dioxide (SiO2) with artificial pigment