Biogenic Material

Vesicular volcanic rock, likely scoria

Scoria; composition commonly basaltic to andesitic, rich in plagioclase and pyroxene

Nephrite Jade

Nephrite

Polished amber agate pendant/beads

Chalcedony (microcrystalline quartz), SiO₂, likely iron-stained yellow-orange agate

Tumbled brown-blue stone, possibly sodalite-bearing jasper

Likely quartz-rich jasper with blue sodalite or dumortierite; identification is uncertain from the image

Banded chert or agate

Microcrystalline quartz (chalcedony), SiO₂

Tumbled gray stone, likely quartz-rich pebble

Probable microcrystalline quartz/chalcedony (SiO₂), possibly gray jasper or quartzite

Red jasper-like chalcedony pebble

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

Red jasper pebble

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

Iron-rich metamorphic rock, likely banded iron formation fragment

Hematite–magnetite-rich quartzite (BIF); Fe₂O₃/Fe₃O₄ with SiO₂

Banded Calcite (often sold as Mexican Onyx or Aragonite)

Calcite/Aragonite (Calcium Carbonate, CaCO3)

Sandstone

Arenite (Clastic Sedimentary Rock)

Quartz

Silicon Dioxide (SiO2)

Black rectangular gemstone pendant, likely obsidian or black glass imitation

Most plausibly black obsidian (volcanic glass; SiO₂-rich), though the image cannot exclude synthetic glass or black onyx

Rhyolitic Tuff

Rhyolitic Tuff / Pyroclastic rock

Rounded brown pebble, likely chert or iron-stained quartzite

Microcrystalline quartz (SiO₂), possibly quartzite; identification is uncertain from the image

Tumbled greenstone or serpentine pebble

Likely serpentinite, composed mainly of serpentine-group minerals (antigorite/lizardite); identification is uncertain from the image alone

Vesicular volcanic rock, likely scoria

Scoria (vesicular basaltic-andesitic rock), composed mainly of plagioclase, pyroxene, and volcanic glass

Botryoidal chalcedony (likely agate/jasper nodule)

Microcrystalline quartz, SiO₂; commonly mixed with iron oxides and clay minerals

Polished green stone, possibly serpentine or nephrite jade

Serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄; alternatively nephrite, a tremolite–actinolite aggregate

Fossil bivalve shell

Likely an extinct or modern-like ribbed cockle/scallop; exact genus requires locality and diagnostic hinge features

Coquina

Bioclastic Limestone

Sandstone

Arenite (primarily SiO2 with Fe2O3)

Colorless faceted gemstone, likely quartz

Quartz (SiO₂), probably rock crystal; exact identification is uncertain from the strongly backlit image

Fossilized shell fragment

Likely calcitic or aragonitic bivalve/gastropod shell; exact taxon indeterminate

Rhyolitic jasper or iron-stained chert

Microcrystalline quartz (SiO₂), likely with hematite/goethite staining

Polished ocean jasper (orbicular jasper)

Microcrystalline quartz/chalcedony with iron- and manganese-bearing inclusions; SiO₂

Petrified Wood

Silicified Wood (primarily SiO2)

Carved labradorite fish

Labradorite, calcium-rich plagioclase feldspar (approximately (Ca,Na)(Al,Si)₄O₈)

Green aventurine (likely)

Quartzite composed mainly of quartz (SiO₂), colored by fuchsite or other chromium-bearing mica

Tumbled yellow jasper or silicified rock fragment

Microcrystalline quartz (chalcedony), SiO₂, likely iron-oxide colored

Tumbled brown jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), commonly with chalcedony and iron oxides

Weathered iron-rich rock, possibly jasper or ironstone

Likely limonite/goethite-bearing siliceous rock; exact identification requires hardness and streak tests

Polished Mexican “Crazy Lace” agate tower

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions

Jasper

Silicon Dioxide (SiO2)

Tumbled dark stone, likely basalt or gabbro

Basalt (fine-grained mafic rock), possibly gabbro; mainly plagioclase and pyroxene

Chrysocolla-bearing copper ore

Chrysocolla (hydrated copper aluminosilicate), commonly with malachite, azurite, quartz, and limonite

Chert (Flint)

Microcrystalline Quartz (SiO2)

Diamond

C (Carbon)

Polished basalt pebble

Basalt, a fine-grained mafic volcanic rock; chiefly plagioclase, pyroxene, and iron-titanium oxides

Red Sandstone

Arenite (SiO2 with Fe2O3)

Weathered gray stone, possibly basalt or granitic rock

Indeterminate fine- to medium-grained silicate rock; possible basalt, diabase, or weathered granite

Likely reddish-brown chert or jasper fragment

Microcrystalline quartz (SiO₂), possibly iron-oxide-bearing jasper