Mineral Like (Natural Glass)

Red Sandstone (Iron-rich)

Arenite (with Hematite cement)

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(F,OH)2)

Ruby

Corundum (Aluminum Oxide with Chromium), Al2O3:Cr

Diamond (in a gold setting)

Carbon (C)

Black Tourmaline (Schorl)

NaFe3+3Al6(BO3)3Si6O18(OH)4

Blue Dyed Agate

Chalcedony (SiO2) with artificial pigment

Dyed Agate

Silicon Dioxide (SiO2) with artificial pigment

Green Chalcedony (likely Chrysoprase or dyed Green Agate)

Silicon Dioxide (SiO2) with nickel impurities or chromium/dye

Amethyst (or Rose Quartz)

Silicon Dioxide (SiO2)

Smoky Quartz and Feldspar Pegmatite

Granitic Pegmatite (chiefly SiO2 and KAlSi3O8)

Tumbled green aventurine (probable)

Quartz, SiO₂, with green fuchsite mica inclusions

Agate

Agate (Silicon Dioxide, SiO2)

Herkimer Diamond

Double-Terminated Quartz (SiO2)

Cupronickel (on a 1981 Mexico 20 Pesos coin)

Copper-Nickel Alloy (Cu75Ni25)

Yellow Quartz (Citrine/Yellow Jasper mix)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous / River-worn Cobble)

Sandstone (SiO2 with iron oxide impurities)

Dyed Blue Agate

Silicon Dioxide (SiO2) with artificial cobalt-based dye

Green Aventurine

Quartz (SiO2) containing Fuchsite (K(Al,Cr)2(AlSi3O10)(OH)2)

Dragon Vein Agate

Chalcedony (cryptocrystalline Quartz), SiO2

Quartz Crystal Cluster on Matrix

Silicon Dioxide (SiO2)

Tumbled jasper, likely red/brown jasper

Microcrystalline quartz (chalcedony), SiO₂, colored chiefly by iron oxides

Yellow Quartz / Citrine Quartz

Silicon Dioxide (SiO2)

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Red Jasper

Silicon dioxide (SiO2) with iron oxide inclusions

Quartz Geode (Citrine or Iron-stained Quartz)

Silicon Dioxide (SiO2)

Ruby (Raw Corundum)

Corundum (Al2O3 with Chromium impurities)

Blue Agate (likely dyed)

Silicon Dioxide (SiO2)

Dyed blue quartz or druzy geode (likely)

Quartz, silicon dioxide (SiO₂), probably artificially colored

Clear quartz sphere or polished quartz cabochon (tentative)

Quartz, silicon dioxide (SiO₂); appearance may also be consistent with ordinary glass, which cannot be ruled out from the image alone

Dyed Blue Agate

Cryptocrystalline Quartz (SiO2)

Pink quartz bead strand (likely rose quartz or pink dyed quartz)

Quartz, silicon dioxide (SiO₂); probable rose quartz variety, possibly dyed or treated quartz/chalcedony

Likely quartz fragment

Quartz (silicon dioxide, SiO₂), possibly milky quartz or quartz-rich rock

Citrine (Quartz variant)

SiO2 (Silicon Dioxide)

Diamond (Faceted)

Diamond (Carbon, C)

Diamond (in jewelry)

Element Carbon (C)

Diamond

Carbon (C)

Amethyst Cluster

Silicon Dioxide (SiO2 with iron impurities)

Diamond

Carbon (C)

Diamond

Diamond (Pure Carbon, C)

Smoky Quartz (with possible Feldspar inclusions)

Silicon Dioxide (SiO2)

Fuchsite or Green Mica Schist

K(Al,Cr)2(AlSi3O10)(OH)2

Quartz (Milky or Smoky Quartz Pebble)

Silicon Dioxide (SiO2)