Mineral (Man Made Glass, Not Natural)

Granodiorite

Granodiorite

Diamond

Carbon (C)

Amethyst

Amethyst (Silicon Dioxide, SiO2 + Fe4+ impurities)

Grey Granite

Phaneritic Felsic Intrusive Igneous Rock

Tumbled greenstone / serpentinite (probable)

Serpentinite, chiefly Mg-rich serpentine minerals (antigorite, lizardite, chrysotile), possibly mixed with chlorite, magnetite, or carbonate

Natural freshwater pearls

Pearl (nacreous calcium carbonate; chiefly aragonite, CaCO₃)

Dark gray rounded stone, possibly basalt or slag

Uncertain; likely fine-grained basalt (plagioclase–pyroxene) or iron-rich industrial slag

Mother of Pearl (Nacre) / Shell Fragment

Biogenic Calcium Carbonate (Aragonite and Conchiolin)

Fossilized coral with attached shell

Likely fossil coral (Scleractinia or Tabulata), with a bivalve or gastropod shell; exact identification requires microscopy

Diamond

Carbon (C)

Green agate/chalcedony bead necklace

Microcrystalline quartz (SiO₂), likely green chalcedony or dyed green agate

Stone bead bracelet

Unidentified polished natural-stone beads; possibly wood-grain jasper, agate, or serpentine

Diamond

Carbon (C)

Titanium Aura Quartz

Titanium-coated Silicon Dioxide (SiO2)

Vesicular basalt (likely scoria)

Basaltic scoria; predominantly plagioclase, pyroxene, and olivine in a mafic volcanic glass/microcrystalline matrix

Tektite

Natural impact glass

Diamond (or Cubic Zirconia)

Carbon (C) or Zirconium Dioxide (ZrO2)

Diamond (in jewelry setting)

Diamond (C - Carbon)

Polished banded agate pendant

Agate, a microcrystalline variety of chalcedony (SiO₂)

Native Silver

Silver (elemental Ag)

Diamond

Carbon (C)

Obsidian

Obsidian (volcanic glass, amorphous silica rich rock)

Blue-green slag glass or chalcedony-like material

Likely industrial glassy slag; exact identification requires testing

Tumbled chalcedony (likely moss or dendritic agate)

Microcrystalline quartz, SiO₂, with iron-oxide inclusions

Asphalt

Asphalt concrete (engineered material, not a naturally occurring rock/mineral in this form)

Polished red jasper beads

Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides

Dark rounded pebble, likely basalt or slag

Probable fine-grained mafic rock; possibly basalt (plagioclase–pyroxene) or industrial iron/steel slag

Prasiolite (Green Quartz) / Sea Glass Amalgam

SiO2 (Silicon Dioxide)

Quartz (Yellow / Citrine Pebble)

Silicon Dioxide (SiO2)

Sandstone

Sandstone (SiO2-rich detrital sedimentary rock)

Green-and-white terrazzo (likely serpentine/marble aggregate)

Composite decorative stone; probable serpentinite (Mg₃Si₂O₅(OH)₄) with white calcite marble fragments in cementitious matrix

Pumice or vesicular volcanic tuff

Pumice: highly vesicular volcanic glass, chiefly rhyolitic to dacitic; possible tuff: lithified ash and pumice fragments

Coquina / Fossiliferous Limestone

Coquina (composed primarily of Calcium Carbonate / CaCO3)

Chert

Microcrystalline Quartz (SiO2)

Sandstone

Sedimentary Clastic Rock

Fired Clay Brick (Anthropic Rock substitute)

Anthropogenic polycrystalline ceramic (predominantly Mullite and Quartz: Al6Si2O13 + SiO2)

Green glass-like cabochon, likely synthetic glass or resin

Unidentified green transparent material; possibly molded glass, synthetic spinel, or resin

Sandstone

Sedimentary Rock (Quartz Sandstone)

Blue slag glass / industrial glass fragment

Artificial silicate glass, composition variable; likely copper- or cobalt-colored furnace slag

Tumbled blue chalcedony (possibly blue agate)

Microcrystalline quartz, SiO₂; chalcedony variety

Hag Stone (Flint with natural hole)

Silicon Dioxide (SiO2) - Nodular Chert / Flint

Slag (Anthropogenic Glass/Iron byproduct)

Ferro-silicate Slag