Organic (Geological Relative)

Ambergris (Geological/Organic Specimen)

Ambra grisea (Produced by Physeter macrocephalus)

Malachite

Malachite, Cu₂CO₃(OH)₂ (basic copper carbonate)

Dark volcanic rock fragment, likely basalt

Basalt; fine-grained mafic rock composed mainly of plagioclase and pyroxene, commonly with minor olivine and magnetite

Cobaltite or cobalt-bearing calcite specimen

Likely erythrite (hydrated cobalt arsenate), Co₃(AsO₄)₂·8H₂O

Polished dark stone, likely basalt or fine-grained mafic rock

Basalt (approximately; commonly plagioclase, pyroxene, and minor olivine/magnetite)

Chrysocolla-bearing copper ore

Chrysocolla, hydrated copper phyllosilicate (approximately (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O), likely mixed with malachite and/or turquoise

Limestone Pebble

Calcium Carbonate (CaCO3)

Basalt

Extrusive Mafic Igneous Rock (composed primarily of plagioclase feldspar and pyroxene)

Fossilized Plant or Tree Bark

Lepidodendron or Sigillaria (example genera)

Likely bituminous coal

Coal, predominantly carbon-rich organic matter with variable maceral and mineral content

Chert (Jasper/Flint variant)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Chert (variations include Flint)

Silicon Dioxide (SiO2)

Sandstone

Arenite

Black Jasper (Etched)

Silicon Dioxide (SiO2) with impurities

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Chert with Limestone matrix

Microcrystalline silica (SiO2) in Calcite (CaCO3) matrix

Basalt Pebble

Basalt (Extrusive Mafic Igneous)

Tumbled black stone, likely obsidian

Obsidian — volcanic glass, chiefly silica-rich rhyolitic composition

Pumice

Vesicular volcanic glass, commonly rhyolitic to dacitic in composition

Tumbled green stone, likely malachite

Malachite (basic copper carbonate, Cu₂CO₃(OH)₂)

Iron-rich laterite or limonite-rich weathered rock

Hydrated iron oxides, chiefly goethite (FeO(OH)) and limonite; possibly ironstone

Vesicular basalt

Basalt; predominantly plagioclase feldspar, pyroxene, and possible olivine

Malachite-bearing matrix specimen

Malachite, Cu₂CO₃(OH)₂, likely with chrysocolla and host rock

Grass (Organic Matter/Soil)

Poaceae (family of monocotyledonous flowering plants)

Chalcedony (variations like Agate or Jasper)

Chalcedony (SiO₂ - microcrystalline quartz)

Chert (Flint variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Jasper

Microcrystalline Quartz (SiO2)

Jasper

Silicon Dioxide (Microcrystalline Quartz, SiO2)

Jasper

Silicon dioxide (SiO2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Fossiliferous Rock (Invertebrate Fossil in Matrix)

Fossiliferous limestone or shaly matrix containing skeletal fossil remains

Weathered granitoid (likely granite or granodiorite)

Granite–granodiorite; primarily quartz, feldspar, and mica

Petrified Wood

Silicified wood (SiO2)

Fossiliferous Kalkstein (Marl/Sandstone)

Fossiliferous calcarenite/siltstone

Basalt Pebble

Extrusive Igneous Rock

Green Fluorite (Beaded)

Fluorite (Calcium Fluoride, CaF2)

Polished basalt pebble

Basalt, a fine-grained mafic volcanic rock; likely containing plagioclase, clinopyroxene, and iron-magnesium minerals

Rounded basalt pebble

Basalt; fine-grained mafic volcanic rock, commonly dominated by plagioclase and pyroxene with possible olivine

Polished black tourmaline pendant (probable)

Schorl tourmaline, NaFe3Al6(BO3)3Si6O18(OH)4

Blue-green botryoidal mineral specimen, likely chrysocolla or chrysocolla-bearing quartz

Chrysocolla (hydrated copper phyllosilicate; variable composition, commonly approximated as (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O)