Mineral, Part Of A Rock

Uncertain blue-white mineral fragment

Possibly calcite or quartz; identification is limited because the specimen is tiny and partly translucent

White quartz pebble or chip

Quartz (silicon dioxide, SiO₂), possibly milky quartz

Weathered granitoid pebble

Likely biotite granite or granodiorite, composed mainly of quartz, feldspar, and mica

Quartz Pebble

Silicon Dioxide (SiO2)

Granite Cobble

Granite

Dark igneous rock, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; commonly plagioclase ± pyroxene, with possible iron-oxide staining

Rounded granite pebble

Granite; primarily quartz, potassium feldspar, plagioclase, and minor biotite/hornblende

Tumbled brown chert (likely flint)

Microcrystalline quartz/chalcedony, SiO₂

Rounded sandstone pebble

Quartz-rich sandstone, likely ferruginous arkose or litharenite

Quartz Pebble

Silicon Dioxide (SiO2)

Chalk (Sedimentary Pebble)

Calcium Carbonate (CaCO3) - Biogenic Limestone

Tumbled reddish-brown stone, likely iron-stained sandstone or quartzite

Probable ferruginous sandstone; exact identification requires testing

Quartz (Granular Milky Quartz fragment)

Silicon Dioxide (SiO2)

Amber

Amber (Amorphous Organic Hydrocarbon)

Yellow Chalcedony (Agate)

Silicon Dioxide (SiO2)

Tangerine Quartz

Silicon Dioxide (SiO2) with Hematite/Limonite coatings

Iron-stained quartz

Quartz (SiO₂), likely limonite/goethite-stained

Beryl (Emerald Variety)

Beryllium Aluminum Silicate (Be3Al2(SiO3)6)

Amethyst (Agate/Chalcedony variety)

Silicon Dioxide (SiO2) with iron impurities

Likely vertebra fossil or bone fragment

Indeterminate fossilized vertebra; mineralized hydroxyapatite, commonly Ca₅(PO₄)₃(OH)

Rounded sandstone pebble

Quartz-rich sandstone, likely arkosic or lithic sandstone

Sandstone fragments

Quartz-rich sandstone (likely), composed mainly of quartz grains cemented by silica, calcite, or iron oxides

Quartz-rich mica schist fragment

Muscovite–quartz schist, likely with feldspar and minor iron oxides

Quartz-rich sandstone or quartzite fragment

Probable quartzite; chiefly microcrystalline quartz (SiO₂), possibly with feldspar and iron-oxide staining

Tumbled quartz-rich pebble

Likely quartzite or quartz-rich sandstone; predominantly SiO₂

Likely weathered iron-rich sandstone or laterite

Ferruginous sandstone; predominantly quartz (SiO₂) cemented or stained by iron oxides such as hematite (Fe₂O₃) and goethite (FeO(OH))

Rounded quartzite pebble

Quartzite; predominantly crystalline SiO₂

Rounded limestone pebble

Limestone, predominantly calcite (CaCO₃)

Fossilized Shell Fragment

Bivalvia or Gastropoda (depending on original organism)

Dark granitic gneiss or fine-grained granite

Biotite granite, possibly weakly foliated gneiss; quartz–feldspar–biotite assemblage

Rounded quartz-rich cobble, likely weathered granite or gneiss

Granite-derived granitoid; chiefly quartz, feldspar, and minor mica/amphibole

Pink Granite (Water-worn Cobble)

Granite (Alkali-feldspar granite)

Polished fossil shark tooth

Likely fossilized shark tooth, possibly Otodus obliquus or a related lamniform shark

Tiger Iron

Banded Iron Formation (BIF)

Granite

Granite (composed primarily of Quartz SiO2, Alkali Feldspar, and Plagioclase Feldspar)

Fossilized Shark Tooth

Chondrichthyes (Class)

Granite Pebble

Felsic Plutonic Rock (primarily Quartz, Feldspar, and Mica)

Granite

Granite (Mainly Quartz, Feldspar, and Mica/Amphibole)

Polished granite pebble

Granite, typically quartz–feldspar–mica aggregate

Tumbled gray pebble, likely basalt or dark chert

Most consistent with fine-grained basalt (plagioclase–pyroxene), though gray chert (microcrystalline SiO₂) is possible

Garnet (Red Garnet)

Garnet Group. The red varieties seen in jewelry are typically Almandine (Fe3Al2(SiO4)3), Pyrope (Mg3Al2(SiO4)3), or a mix of the two (pyrope-almandine series).

Honey calcite (likely calcite-rich marble or vein fragment)

Calcite, calcium carbonate (CaCO₃)