Not A Natural Rock (Man Made Composite)

Rutilated Quartz

Quartz with Rutile inclusions (SiO2 with TiO2)

Chert (with nodule)

Microcrystalline Quartz (SiO2)

Weathered iron-rich sandstone or laterite

Ferruginous sandstone; chiefly quartz (SiO₂) cemented or stained by iron oxides such as hematite and goethite

Diamond

C (Carbon)

Dyed Chalcedony (Agate)

Silicon Dioxide (SiO2) with artificial pigment

Blue Topaz (Cut Gemstone)

Aluminum silicate fluoride hydroxide (Al2SiO4(F,OH)2)

Green Agate

Silicon Dioxide (SiO2) - Variety of Chalcedony

Faceted yellow-brown gemstone earring

Likely citrine (quartz, SiO₂), though treated quartz or synthetic glass cannot be confirmed from the image

Citrine

Silicon Dioxide (SiO2)

Chert (often called Flint or Jasper if reddish)

Microcrystalline Quartz (SiO2)

Diamond

Carbon (C)

Quartzite

Metamorphic Quartz (SiO2)

Diamond (Faceted)

Carbon (C)

Milky quartz (likely)

Quartz, silicon dioxide (SiO₂)

Tektite (Indochinite)

Impactite (Natural Glass)

Citrine and Quartz

Silicon Dioxide (SiO2)

Chert Arrowhead

Chert (Cryptocrystalline variety of Quartz, SiO2)

Pyrite

Iron Sulfide (FeS2)

Tumbled blue-dyed stone, likely basalt or blue aventurine

Likely fine-grained basalt (plagioclase and pyroxene), possibly coated or dyed; exact identification requires testing

Red synthetic corundum (ruby-colored lab-grown sapphire)

Corundum, aluminum oxide (Al₂O₃), likely synthetic and chromium-colored

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Bornite (Peacock Ore)

Bornite (Cu5FeS4)

Chert (Flint/Chalcedony)

Silicon Dioxide (SiO2)

Diamond

Natural Carbon (C)

Amethyst

Silicon Dioxide (SiO2)

Diamond (or Cubic Zirconia)

Carbon (C) or Zirconium Dioxide (ZrO2)

Citrine

Citrine (Silicon Dioxide, SiO2)

Citrine Quartz

Crystalline Quartz (SiO2) with iron impurities

Mother of Pearl (Nacre)

Calcium Carbonate (Aragonite) with organic conchiolin

Chert (often called Flint)

Chert (SiO2)

Emerald

Beryl (Be3Al2(SiO3)6) with trace Chromium/Vanadium

Tumbled jasper or quartzite pebble

Jasper (microcrystalline quartz, SiO₂), possibly iron-stained quartzite

Coquina Limestone

Coquina (Biogenic Limestone)

Citrine Quartz

Macrocrystalline Quartz (SiO2)

Ruby in Zoisite

Anyolite (composite of Corundum [Al2O3] and Zoisite [Ca2Al3(SiO4)(Si2O7)O(OH)])

Polished blue-banded agate slice

Agate (microcrystalline quartz, SiO₂; chiefly chalcedony)

Yellow Quartz (Citrine Quartz Pebble)

Silicon Dioxide (SiO2)

Brown Chert

Microcrystalline Quartz (SiO2)

Dyed Blue Agate

Chalcedony (SiO2) with artificial dye

Flint (or Chert with cortex)

Silicon dioxide (SiO2)

Chert (Yellow Jasper/Flint)

Chert (Microcrystalline Silicon Dioxide, SiO2)

Granite

Granite