Undetermined

Small dark mineral/rock fragment

Indeterminate; possibly biotite-rich schist, graphite, or metallic sulfide

Quartz vein fragment (likely quartz with dark host rock)

Quartz (SiO₂) in an unidentified fine-grained host rock

Mixed polished rock/mineral specimens

Indeterminate from image; likely quartz-bearing material with iron-oxide staining and possibly mica-rich schist

Black polished stone or mineral fragment

Unidentified opaque dark mineral; possibilities include black tourmaline (schorl), obsidian, or hematite

Iron-oxide-stained rock (likely limonite/goethite-rich material)

Goethite (α-FeO(OH)) and/or limonite, an iron-oxide/hydroxide mixture coating a rock matrix

Small pale mineral/rock fragment

Indeterminate; possibly weathered quartz, calcite, or light-colored limestone

Weathered granitoid (likely granite or granodiorite)

Quartz–feldspar plutonic rock; exact type cannot be confirmed from the photograph

Likely dark mineral or rock fragment

Indeterminate from image; possibly a dark silicate mineral such as hornblende, biotite, or basalt

Small brown pebble or mineral fragment

Indeterminate from image; possibly iron-stained quartz, ironstone, or a dark mineral grain

Unidentified gray rock/mineral specimen

Indeterminate; possibly quartz-rich rock or a metallic sulfide-bearing specimen

Small pale-gray stone, likely a water-worn quartzite or chert pebble

Undetermined; possibly quartzite (predominantly SiO₂)

Small pale-green mineral fragment

Undetermined; possibly green quartz or calcite

Rounded brown pebble, possibly quartzite

Undetermined; quartzite is a tentative visual identification

Cut purple gemstone, likely synthetic cubic zirconia or glass

Undetermined; possible cubic zirconia (ZrO₂)

Small pale stone, likely quartz-rich rock

Undetermined; possibly milky quartz or quartzite

Dark, coarse-grained rock (possibly mafic igneous rock)

Undetermined; potentially basaltic or gabbroic material

Tumbled light-colored stone, possibly quartz or agate

Undetermined; likely microcrystalline quartz (SiO₂)

Small porous rock (possibly vesicular volcanic rock)

Undetermined; possibly vesicular basalt or scoria

Small polished pebble, likely quartz or quartzite

Undetermined; possibly quartzite (quartz, SiO₂)

Weathered rock fragment

Undetermined; possibly a coarse-grained granitoid

Small dark rock fragment (not identifiable from the image)

Undetermined; no diagnostic mineral features are visible

Possibly tumbled dark stone

Undetermined; appearance alone is insufficient for identification

Small polished stone, possibly a dark agate or jasper pebble

Undetermined; likely microcrystalline quartz (SiO₂)

Possible weathered sandstone or iron-rich sedimentary rock

Indeterminate; likely quartz-rich sandstone with iron-oxide cement

Small rounded light-colored mineral pebble

Indeterminate; possibly quartz, feldspar, or calcite

Polished fossil shell or crinoid fragment

Likely calcitic fossil, possibly a bivalve shell; exact identification requires clearer detail

Blue glassy gemstone-like specimen

Indeterminate; possibly dyed or treated turquoise, blue apatite, or man-made glass

Dyed or synthetic turquoise-blue glass-like specimen

Likely man-made colored glass or resin; exact identification requires testing

Fossilized bone fragment

Permineralized vertebrate bone, likely mammalian or reptilian; exact identification requires microscopy

Rounded river pebble, likely quartz-rich sandstone or fine-grained granite

Indeterminate from photograph; possible quartz/feldspar-bearing granitic pebble

Likely calcite-rich limestone

Calcite (CaCO₃), possibly recrystallized limestone

Rounded fossil fragment, possibly fossiliferous limestone

Unidentified carbonate fossil or fossil-bearing limestone; exact fossil cannot be determined from the photograph

Iron-rich meteorite candidate

Probable stony-iron or iron meteorite; exact classification requires testing

Small pale stone (undetermined)

Unidentified geological specimen; image lacks detail for a reliable mineral or rock identification

White quartz pebble

Quartz (silicon dioxide, SiO₂)

Milky quartz (with iron-oxide staining)

Quartz, silicon dioxide (SiO₂)

Likely limestone or calcareous fossil fragment

Calcite-rich carbonate rock; possibly bioclastic limestone (CaCO₃)

Small tan stone (undetermined)

Unidentified fine-grained geological material; species cannot be determined from the image

Small brown pebble, possibly iron-stained quartz or chert

Undetermined; likely quartz-rich rock (SiO₂)

Light-colored, weathered rock fragment

Undetermined; possibly weathered granite or granitic rock

Small polished pink-and-white pebble, possibly quartz or feldspar

Undetermined; likely a quartz- or feldspar-rich silicate

Small cream-colored tumbled stone, possibly quartz or feldspar

Undetermined; appearance alone is insufficient to identify the mineral