Organic (Often Found By Beachcombers)

Galena

Lead(II) sulfide (PbS)

Specular Hematite

Specularite (Iron Oxide, Fe2O3)

Tourmaline (likely Schorl)

Tourmaline Group Mineral (e.g., Schorl for black varieties); (Na,Ca)(Li,Mg,Fe,Mn,Al)3Al6(BO3)3Si6O18(OH)4

Hag Stone

Porous sedimentary rock (typically Flint, Chert, or Sandstone) with naturally occurring holes

Ironstone Concretion

Siderite or Limonite Concretion

Chert (Jasper variation)

Microcrystalline Quartz (SiO2)

Sandstone (Ferruginous)

Arenite (complex silicate composition with iron oxides)

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Coal

Bituminous or Anthracite coal (carbon-rich sedimentary rock)

Milky Quartz

Silicon dioxide (SiO2)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (Fe-rich)

Sandstone

Arenite (composed primarily of SiO2)

Gastropod Internal Mold (Steinkern)

Class Gastropoda fossil mold (Phylum Mollusca)

Chert (specifically Blue Chert/Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Gold Ore in Quartz/Schist

Auriferous Quartz and Sulfide-bearing Schist

Quartz with Iron Staining

Silicon Dioxide (SiO2) with Hematite/Limonite inclusions

Malachite

Copper Carbonate Hydroxide [Cu2CO3(OH)2]

Red Jasper

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with iron oxide staining/cementing)

Howlite and Purpurite druzy

Calcium Borosilicate Hydroxide (Howlite) and Manganese Phosphate (Purpurite)

Gneiss (Metamorphic Cobble)

Gneiss (High-grade Regional Metamorphic Rock)

Chert (Arrowhead Fragment)

Chert / Microcrystalline Silicon Dioxide (SiO2)

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Citrine (likely Heat-Treated Amethyst)

Silicon Dioxide (SiO2)

Amazonite

KAlSi3O8 (Potassium Aluminum Silicate)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Jadeite

NaAlSi2O6 (Sodium Aluminum Silicate)

Red Quartzite / Jasper-rich Pebble

Quartzite (primarily SiO2 with hematite inclusions)

Sandstone (Quartzite Pebble)

Arenite / Metamorphosed Sandstone (SiO2)

Scoria (Lava Rock)

Extrusive Igneous Scoria (Vesicular Basalt)

Rose Quartz

Silicon Dioxide with traces of titanium, iron, or manganese (SiO2)

Botryoidal Chalcedony

Silicon Dioxide (SiO2)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Ocean Jasper

Spherulitic Chalcedony (SiO2)

Shale

Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)

Chert (Iron-stained)

Chert (SiO2 - Silicon Dioxide)

Red Quartzite (River Pebble)

Quartzite (primarily Silicon Dioxide - SiO2)

Chert (varieties include Flint and Jasper)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Fuchsite

Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)

Schist (Graphite or Mica rich)

Crystalline Schist (often containing Muscovite, Biotite, or Graphite)