Organic Material (Likely A Fruit Or Berry)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Tumbled basalt (likely)

Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase feldspar and pyroxene, often with minor olivine and iron oxides

Ocellar Rhyolite

Rhyolite (featuring orbicular/ocellar quartz and feldspar textures)

Rounded gray-brown river pebble

Indeterminate lithic clast; likely weathered sandstone or fine-grained metamorphic rock

Tumbled dark stone, likely basalt

Basalt (fine-grained mafic volcanic rock; commonly plagioclase, pyroxene, and minor olivine)

Banded iron formation fragment (likely jasper-rich ironstone)

Banded iron formation (BIF), commonly hematite/goethite with chert or jasper; Fe₂O₃/FeO(OH) and SiO₂

Granite (likely weathered quartz-bearing granite)

Granite; primarily quartz, feldspar, and mica/amphibole

Tumbled brown translucent stone, likely quartz/jasper

Microcrystalline quartz (SiO₂), possibly iron-stained chalcedony or jasper

White quartz pebble (likely milky quartz)

Quartz, silicon dioxide (SiO₂)

Brecciated jasper (likely ocean jasper or rhyolitic jasper)

Silica-rich volcanic breccia composed mainly of microcrystalline quartz/chalcedony (SiO₂), with iron-oxide staining and possible feldspar

Black polished/tumbled stone, likely basalt or black jasper

Most likely fine-grained basalt (plagioclase and pyroxene); appearance can also match microcrystalline quartz (black jasper)

Chert (often colloquially referred to as Flint)

Chert (Cryptocrystalline Quartz, SiO2)

Chert (Jasper/Iron-stained Quartzite)

Silicon Dioxide (SiO2)

Micaceous schist (probable)

Mica schist, dominated by muscovite/biotite with quartz and feldspar

Iron-stained quartzite or quartz-rich sandstone

Quartzite, predominantly SiO₂, with iron-oxide staining

Likely milky quartz with iron-oxide inclusions

Quartz, silicon dioxide (SiO₂)

Polished brecciated jasper (likely orbicular/picture jasper)

Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide staining and breccia fragments

Iron-rich meteorite candidate

Undetermined Fe–Ni meteorite, possibly an ordinary chondrite or iron meteorite

Quartz-bearing iron-rich rock, possibly quartzite or hydrothermal breccia

Quartz (SiO₂) with iron oxides/hydroxides, likely limonite/goethite; exact host rock is uncertain from the photograph

Sandstone

Arenite (composed primarily of SiO2)

Likely metallic meteorite fragment

Unclassified iron-rich meteorite; possible stony-iron or iron meteorite

Coquina Limestone (Fossiliferous Limestone)

Calcareous bioclastic sedimentary rock (CaCO3)

Quartzite and Chert

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Weathered iron-rich rock, possibly laterite or altered basalt

Probable ferruginous basalt/lat eritic material; exact identification requires testing

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Serpentinite (likely serpentinized ultramafic rock)

Serpentine-group minerals, chiefly antigorite/lizardite; commonly derived from peridotite

Granite or granitic pegmatite fragment

Felsic intrusive rock, chiefly quartz, feldspar, and mica

Sandstone

Arenite (primarily SiO2)

Tumbled chalcedony (likely milky quartz)

Chalcedony, cryptocrystalline SiO₂; possibly quartz-rich chert

Limestone (Weathered Pebble)

Calcium Carbonate (CaCO3) / Limestone

Iron-rich breccia (likely hematite–goethite breccia)

Hematite (Fe₂O₃) and goethite (FeO(OH)) in a silicified or iron-cemented breccia

Banded chert (likely flint)

Microcrystalline quartz/chalcedony, SiO₂

Porphyritic polymictic breccia (likely volcanic breccia)

Volcanic breccia; probable polymictic andesite–dacite breccia with quartz/feldspar clasts

Chert (Smooth River Stone)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (specifically Iron-stained River Cobble)

Silicon Dioxide (SiO2)

Dark coarse-grained rock, likely basalt or gabbro

Basalt (fine-grained) or gabbro (coarse-grained), composed mainly of plagioclase feldspar and pyroxene

Chert (specifically Jasper)

Silicon dioxide (SiO2) with iron oxide inclusions

Petrified Wood

Silicified Wood (SiO2)

Polished orbicular jasper (likely ocean jasper)

Silicified volcanic rock; chiefly microcrystalline quartz (SiO₂), with feldspar and iron-rich alteration minerals

Chert (Jasper/Agate)

Cryptocrystalline Quartz (SiO2)