Not A Rock (Man Made Polymer)

Chert (Nodule)

Microcrystalline Quartz (SiO2)

Lapis Lazuli

Lapis Lazuli (a rock type, not a single mineral, composed primarily of lazurite, calcite, and pyrite)

Green Glass Cullet / Recycled Glass

Amorphous Silicon Dioxide (SiO2) with various metal oxides

Chert (or Flint)

Chert (a cryptocrystalline variety of quartz, SiO2)

Red Sandstone

Arenite (with Iron Oxide / Hematite staining)

Diamond

Carbon (C)

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite

Rough Diamond

Diamond (pure Carbon, C)

Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite

Chert / Flint

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Fossilized Shell in Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Coquina

Coquina (Bioclastic Limestone)

Chert (Common Opal/Jasper variety)

Cryptocrystalline Quartz (SiO2)

Chert (Jasper Variant likely)

Silicon Dioxide (SiO2)

Metal Alloy (Jewelry)

Not a naturally occurring rock or mineral; likely a metal alloy for jewelry. Possible compositions include sterling silver (92.5% silver, 7.5% copper), or other silver/gold alloys.

Chert (often called Flint)

Chert (Cryptocrystalline Quartz, SiO2)

Pebble

Clast (specifically a granule or small pebble)

Coquina

Coquina (Biogenic Limestone / CaCO3)

Chert (varieties include Flint and Mudstone)

Microcrystalline Silica (SiO2)

Chert (with Desert Varnish/Iron Stain)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Coquina / Fossiliferous Limestone

Coquina (composed primarily of Calcium Carbonate / CaCO3)

Diorite

Diorite

Carnelian

Chalcedony (cryptocrystalline quartz), SiO2

Jade

Jade can refer to two distinct minerals: Nephrite (a variety of the mineral actinolite, Ca2(Mg,Fe)5Si8O22(OH)2) and Jadeite (Na(Al,Fe3+)Si2O6). Based on the image, showing a relatively uniform green color and possibly slight translucence in bead form, it is very likely one of these, but determining which one from a photo is difficult without specific testing.

Amber

Fossilized tree resin (not a true mineral as it is organic and amorphous); Chemical formula is highly variable, but often approximated as C10H16O.

Rough Diamond

Diamond (pure Carbon, C)

Tektite (Indochinite)

Tektite (Amorphous Silica Glass)

Natural Pearl (appearing in a jewelry setting)

Calcium Carbonate (mostly Aragonite), CaCO3 with Conchiolin

Basalt

Basalt

Smoky Quartz

Silicon Dioxide (SiO2) with trace aluminum and irradiation

Jasper Marble

Silicon Dioxide (SiO2) with Impurities

Pearl

Calcium Carbonate (CaCO3) with Conchiolin

Natural or Cultured Pearl

Calcium Carbonate (Aragonite and Conchiolin), CaCO3

Chert (Common Variety, Jasper)

Microcrystalline Quartz (SiO2)

Chert (Nodule)

Chert (Alpha-Quartz, SiO2)

Petrified Wood (Silicified Wood)

Silicified Paleoflora (mainly Quartz, SiO2)

Smoky Quartz

Smoky Quartz (Silicon Dioxide, SiO2)

Chert / Flint

Silicon Dioxide (SiO₂)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

White Jade (Nephrite)

Nephrite, Ca2(Mg,Fe)5Si8O22(OH)2

Banded Calcite or Travertine

Calcium Carbonate (CaCO3)

Chert (and/or Flint)

Microcrystalline Quartz (SiO2)