Sedimentary (If Natural Jasper) Or Artificial (If Slag)

Polished dark stone, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine

Likely weathered quartz-rich rock fragment

Uncertain; possibly quartz sandstone or a pale feldspathic rock

Likely obsidian (possibly tektite or slag glass)

Volcanic glass; primarily SiO₂, noncrystalline

Dark river pebble, likely basalt or fine-grained volcanic rock

Basalt (probable); mostly plagioclase and pyroxene, with possible magnetite

Tumbled yellow jasper or chert

Microcrystalline quartz (SiO₂), likely iron-stained jasper/chert

Dyed and polished agate beads

Chalcedony (microcrystalline quartz), SiO₂; commonly agate

Tumbled brown stone, possibly jasper or iron-rich quartz

Uncertain; likely microcrystalline quartz (SiO₂) with iron-oxide inclusions

Tumbled jasper and agate assortment

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide and other mineral impurities

Black Onyx

Onyx (Silicon Dioxide, SiO2)

Rounded dark river pebble, likely basalt

Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase feldspar and pyroxene, commonly with minor olivine and iron oxides

Polished jasper, likely orbicular or brecciated jasper

Jasper: microcrystalline quartz (chalcedony), SiO₂, colored by iron oxides and other inclusions

Chert (Yellow Jasper)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Chert (flint)

Microcrystalline quartz, SiO₂ (chalcedony/quartz)

Weathered limestone or calcareous concretion

Calcite-rich carbonate rock; chiefly calcium carbonate (CaCO₃)

Polished black obsidian

Volcanic glass; predominantly rhyolitic silica (SiO₂), with minor iron, magnesium, and alkalis

Polished ocean jasper (orbicular jasper), probable

Silicified orbicular rhyolite; chiefly microcrystalline quartz (SiO₂)

Tumbled black stone, likely basalt or black jasper

Basalt (fine-grained plagioclase–pyroxene rock), possibly opaque microcrystalline quartz/jasper

Red jasper (likely polished/tumbled)

Jasper, microcrystalline quartz (SiO₂) colored by iron oxides

Brecciated Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Polished jasper (likely brecciated or red jasper)

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide pigments and possible breccia fragments

Banded chert (likely jasper/chert pebble)

Microcrystalline quartz, SiO₂, with iron-oxide and clay/mineral impurities

Yellow chalcedony or citrine-like polished stone

Chalcedony (microcrystalline quartz, SiO₂), possibly dyed or artificially illuminated; exact identification is uncertain from the image

Bismuth

Bismuth (Bi)

Dark metallic-looking mineral specimen, possibly magnetite

Magnetite (Fe₃O₄), tentative identification

Dyed Blue Agate

Cryptocrystalline Quartz (SiO2)

Tumbled brown chalcedony or jasper pebble

Microcrystalline quartz, SiO₂; possibly iron-rich jasper

Blue Agate (Tumbled and Dyed)

Silicon Dioxide (SiO2) with likely organic dyes

Tumbled brown chert or jasper pebble

Microcrystalline quartz (SiO₂), likely iron-oxide-bearing chert/jasper

Conglomerate (possibly breccia)

Polymictic clastic conglomerate; rounded clasts in a dark, likely volcanic-lithic matrix

Weathered limestone or calcareous sandstone

Calcite-rich carbonate rock, predominantly CaCO₃; possibly fossiliferous limestone

Chert (Green Fossilized Algae or Jasper)

Silicon Dioxide (SiO2)

Chert (specifically Yellow Jasper variety)

Silicon Dioxide (SiO2)

Smoky Quartz

Silicon Dioxide (SiO2)

Bornite (Peacock Ore)

Bornite (Cu5FeS4)

Asphalt concrete

Anthropogenic conglomerate

Basalt cobble

Mafic volcanic rock, chiefly plagioclase, pyroxene, and often olivine

Native copper nugget

Native copper (Cu)

Gray sandstone or weathered volcanic rock

Likely quartz-rich sandstone; exact identification is uncertain from the image alone

Metallic sulfide mineral fragment, likely bornite or chalcopyrite

Bornite (Cu₅FeS₄) or chalcopyrite (CuFeS₂)

Polished picture jasper

Silicified microcrystalline quartz (chalcedony), commonly called picture jasper

Polished banded chert or jasper

Microcrystalline quartz (SiO₂), likely iron- and manganese-stained chert/jasper

Unidentified rock fragments

Indeterminate; likely a weathered, iron-stained silicate rock