Mineral, Specifically A Rock Fragment

Pink Granite

Granite (composed primarily of Quartz, K-Feldspar, and Plagioclase)

Banded Gneiss

Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Mica)

Milky Quartz

Silicon Dioxide (SiO2)

Likely quartz-rich rock fragment

Indeterminate; possibly quartz-bearing granite or quartzite

Small brown mineral fragment

Unidentified; the image lacks enough detail for a reliable species-level identification

Conglomerate

Conglomerate (clastic sedimentary rock)

Weathered sandstone or arkosic sandstone

Clastic sandstone, likely quartz–feldspar-rich (arkose)

Sandstone (specifically Cross-bedded Sandstone)

Arenite (composed primarily of SiO2)

Limestone (specifically Fossiliferous or Crinoidal Limestone)

Calcium Carbonate (CaCO3) - Calcite Rock

Feldspar (specifically Orthoclase)

Potassium Aluminum Silicate (KAlSi3O8)

Small pale stone fragment (undetermined)

Unidentified; the image lacks diagnostic detail for a reliable identification

Chert (specifically Pink/Tan Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Jasper Breccia

Silicon Dioxide (SiO2) with iron inclusions

Painted Rock / Geode Specimen

Silicon Dioxide with artificial pigment coating

Red Sandstone

Arenite (primarily Quartz with Hematite cement)

Chrysotile Asbestos

Mg3Si2O5(OH)4

Sedimentary Rock (Limestone or Siltstone pebble)

Sedimentary rock fragment

Small cylindrical mineral/stone fragment

Undetermined; the image is insufficient for reliable mineral identification

Fossiliferous Limestone with Brachiopod Mold

Calcium Carbonate (CaCO3) matrix containing Brachiopoda fossil impressions

Small pale blue-gray rock fragment

Unidentified fine-grained silicate rock; image insufficient for a reliable species-level identification

Small dark mineral fragment

Undetermined; image lacks diagnostic detail for reliable identification

Leopard Skin Jasper

Orbicular Jasper (Silicon Dioxide, SiO2)

Chert (specifically a weathered Chert nodule or fragment)

Chert; Microcrystalline or Cryptocrystalline Quartz (SiO2)

Smooth river pebble (exact rock type indeterminate)

Unidentified rounded lithic clast; composition cannot be determined from the photograph

Sedimentary Pebble

Sedimentary Rock Fragment

Yellow-brown stone or mineral fragment

Unidentified; the image does not show enough detail for a reliable identification

Polished brecciated jasper (likely)

Brecciated jasper, an opaque microcrystalline quartz (SiO₂) with contrasting silica-rich fragments and matrix

Possible iron-rich pebble with a weathered inclusion

Unidentified; image alone does not support a reliable mineral or rock identification

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Iron-stained rock fragment, possibly quartz-rich

Unidentified quartz-rich rock with iron-oxide staining (likely hematite/goethite)

Crushed stone aggregate

Mixed lithic aggregate; individual fragments cannot be identified from the image

Quartz-rich rock fragment

Unidentified quartz–feldspar-rich rock; exact lithology cannot be determined from the image

Small brown mineral or rock fragment

Undetermined; the image does not show enough detail for reliable identification

Quartz-bearing rock fragment

Likely quartz with iron-oxide staining; exact rock type cannot be determined from the image

Crushed Stone Ballast

Crushed Limestone or Granite Aggregate

River Pebble

Polished Rock Fragment

Granite / Gneiss Ballast Rock

Granite (Quartzo-feldspathic rock)

Labradorite

(Ca, Na)(Al, Si)4O8

Sandstone

Arenite (specifically Quartz Arenite)

Dalmatian Jasper

Feldspar porphyry (Microcline and Quartz with Arfvedsonite spots)

Sandstone

Arenite (specifically Quartz Arenite)

Pallasite Meteorite

Pallasite (Stony-iron meteorite; Fe-Ni alloy with (Mg,Fe)2SiO4 olivine)