Anthropogenic Material

Fossil-bearing limestone with a probable fossil shell

Fossiliferous limestone; the visible fossil may be a gastropod or other shelly fossil, but the image is not diagnostic enough for species identification.

Brown chert (likely flint)

Microcrystalline quartz (SiO₂), chiefly chalcedony

Limestone

Calcareous sedimentary rock (CaCO3)

Limestone

Calcium carbonate (CaCO3)

Tumbled quartz-rich pebble, likely jasper or chert

Microcrystalline quartz (SiO₂), possibly iron-stained jasper

Fossil scallop shell

Bivalve mollusk shell, likely family Pectinidae; primarily calcite (CaCO₃)

Rounded quartz-rich pebble

Lithic pebble; likely quartz/quartzite with iron-oxide staining

Rounded brown pebble, likely weathered basalt or iron-rich chert

Indeterminate; possibly basalt (fine-grained mafic silicate rock) or ferruginous chert

Fossil oyster shell

Ostrea or Exogyra sp. (identification uncertain)

Mudstone

Argillite / Siliciclastic sedimentary rock

Serpentine

Serpentine group ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al)2O5(OH)4)

Tumbled brown pebble

Indeterminate; likely quartz-rich sandstone or chert

Banded gneiss pebble

Biotite–quartz–feldspar gneiss (composition variable)

Petrified wood

Silicified wood, chiefly microcrystalline quartz (SiO₂)

Tumbled jasper or rhyolitic porphyry

Silicic volcanic rock, likely rhyolite (quartz- and feldspar-rich), possibly jasperized

Quartz / Quartzite

Silicon Dioxide (SiO2)

Sandstone

Arenite (primarily SiO2)

Sandstone (Tumbled/River Pebble)

Arenite (composed primarily of SiO2)

Limestone

Calcite (CaCO3)

Chert Pebble

Microcrystalline Quartz (SiO2)

Likely bituminous coal or carbon-rich shale fragment

Bituminous coal; predominantly carbon with macerals and minor clay/pyrite

Raw Diamond

Carbon (C)

Diamond

Carbon (C)

Chintz

Microcrystalline Quartz (SiO2)

Diamond

Carbon (C)

Chalcedony

Silicon dioxide (SiO2)

Diamond

Carbon (C)

Likely brown chert (flint)

Microcrystalline quartz (SiO₂), variety chert/flint

Diamond (or diamond simulant)

C

Polished bumblebee jasper bead

Bumblebee jasper (trade name); chiefly calcite, aragonite, and pyrite, with variable realgar/orpiment and other minerals

Slag (Industrial Glass Slag)

Amorphous Silicate Glass (often containing Al, Ca, Mg, and Ti oxides)

Tiger’s-eye

Chatoyant quartz (SiO₂), typically pseudomorphous quartz after crocidolite

Orbicular rhyolite (orbicular jasper-like volcanic rock)

Silica-rich rhyolite containing concentric feldspar–quartz orbicules, commonly with iron-oxide staining

Banded metamorphic rock, likely gneiss or amphibolite

Composition uncertain; probable quartz–feldspar–amphibole assemblage

Carved Stone Turtle

Carved Soapstone and Quartz

Opalite-style glass pendant

Man-made opalescent glass (not natural opal)

Tumbled greenstone, likely serpentine or altered basalt

Serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄; possibly chlorite/epidote-bearing mafic rock

Tumbled yellow quartz (likely citrine or iron-stained quartz)

Quartz, SiO₂; yellow color from trace iron or irradiation/heat-related coloration

Banded Calcite (Onyx Marble / Green Onyx)

Travertine / Banded Calcite (CaCO3) or Aragonite

Iron-stained quartz-rich rock, possibly weathered granite or pegmatite

Quartz–feldspar rock with iron-oxide alteration; exact identification is uncertain from the photograph

Flint / Chert

Silicon dioxide (SiO2)

Flint Pebble

Sedimentary cryptocrystalline quartz (SiO2)