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

Iron-rich concretion or weathered ironstone

Goethite–hematite limonite aggregate; commonly described as limonite or ironstone

Blue Agate Slice

Chalcedony (SiO2)

Quartz Geodes and Crystal Clusters

Silicon Dioxide (SiO2)

Chert (Honey Chert / Flint)

Silicon Dioxide (SiO2)

Graphite

Graphite (Carbon, C)

Polished brecciated jasper pebble

Microcrystalline quartz (SiO₂), with iron-oxide inclusions

Chert (Flint variety)

Chert (Cryptocrystalline Quartz, SiO2)

Chert (Yellow Jasper)

Microcrystalline Quartz (SiO2)

Dalmatian jasper

Orbicular microcrystalline quartz rock, commonly rhyolitic or volcanic-feldspar matrix with black arfvedsonite/alkali-amphibole inclusions

Tiger’s eye

Quartz variety, primarily silicon dioxide (SiO₂); fibrous quartz pseudomorph after crocidolite asbestos

Red jasper pebble

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

Green Chalcedony (Batu Akik)

Silicon Dioxide (SiO2)

Yellow Quartz (Citrine/Yellow Jasper mix)

Silicon Dioxide (SiO2)

Chert (Green Jasper)

Microcrystalline Quartz (SiO2) with iron silicate inclusions

Black Onyx

Chalcedony (SiO2)

Red jasper-like chalcedony pebble

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

Yellow Quartz (Citrine or Yellow Jasper)

Silicon Dioxide (SiO2) with iron impurities

Polished yellow jasper or opaque chalcedony bead

Microcrystalline quartz (SiO₂), likely iron-oxide-stained jasper

Chert (Field Stone)

Silicon Dioxide (SiO2)

Tumbled jasper or chert

Microcrystalline quartz (SiO₂), possibly iron-bearing jasper

Jasper or Agate-bearing Chert

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Ferruginous Conglomerate (or Iron-Rich Concrete/Slag)

Clastic Sedimentary (Silicon Dioxide/Iron Oxide matrix)

Pearls

Aragonite (calcium carbonate) and Conchiolin

Green Chalcedony (likely Green Agate or Chrysoprase)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Blue Agate (Dyed Chalcedony)

Silicon Dioxide (SiO2)

K2 Stone (or K2 Jasper)

Azurite-in-Granite (Potassium Feldspar, Quartz, Plagioclase, Muscovite, and Azurite)

Terrazzo (Man-made Composite)

Cementitious or Resin-bound Lithic Composite

Yellow chalcedony (likely citrine or iron-stained quartz)

Microcrystalline quartz, SiO₂; yellow coloration likely from iron oxides or included quartz varieties

Jasper

Silicon Dioxide (SiO2) with impurities

Agate (specifically, multi-colored or pastel-dyed agate)

Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).

Peacock ore (iridescent chalcopyrite, possibly bornite)

Chalcopyrite, CuFeS₂; the iridescent surface may be natural tarnish or artificial acid treatment. Similar material is bornite, Cu₅FeS₄.

Tumbled jasper or quartzite pebble

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

Sandstone (likely Greywacke or Siltstone variety)

Arenite / Siltstone (primarily SiO2)

Polished Tumbled Stone (Dark Chalcedony / Jasper)

Silicon Dioxide (SiO2)

Chert (Green and Black Jasper variant)

Cryptocrystalline Quartz (SiO2)

Red jasper (likely iron-rich chalcedony/jasper)

Jasper, microcrystalline quartz (SiO₂), colored mainly by hematite/goethite

Sandstone

Sandstone (SiO2-rich detrital sedimentary rock)

Red jasper (tumbled river pebble)

Jasper, an opaque microcrystalline variety of quartz/chalcedony (SiO₂), colored mainly by iron oxides

Brick fragment (Man-made material)

N/A (Fired clay)

Tumbled yellow-brown translucent stones, likely quartz/chalcedony

Quartz (SiO₂) or microcrystalline quartz (chalcedony); exact identification requires testing

Red Jasper and Hematite

Silicon Dioxide (SiO2) and Iron Oxide (Fe2O3)

Polished brecciated jasper

Jasper, opaque microcrystalline quartz (SiO₂), likely brecciated jasper with iron-oxide and dark silicate inclusions