Not A Rock (Man Made Origin)

Tumbled black obsidian (likely)

Volcanic glass; chiefly silica-rich rhyolitic glass (SiO₂)

Blue sea glass or blue glassy mineral fragment

Uncertain; likely man-made soda-lime glass, not a natural mineral

Blue glassy fragment among beach gravel

Likely cobalt-blue man-made glass; not a natural mineral specimen

Opalite

Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)

Diamond (Cut Gemstone)

Natural Carbon (C)

Druzy quartz specimen

Quartz, SiO₂, with possible iron-oxide staining and minor associated minerals

Libyan Desert Glass

Impact-melt silica glass (SiO2 + traces of Al, Fe, Ti)

Clear faceted gemstone in an ornate metal bracelet

Unidentified transparent faceted stone; possibilities include quartz (SiO₂), zircon (ZrSiO₄), or glass—image alone cannot distinguish them

Tumbled granite

Granite, a coarse-grained felsic intrusive igneous rock

Marble

Marble (metamorphosed limestone/dolostone). Predominantly composed of Calcite (CaCO3) for marble derived from limestone, or Dolomite (CaMg(CO3)2) for marble derived from dolostone.

Granite

Granite (Plutonic Igneous Rock)

Rounded quartz-rich river pebble

Likely quartz-bearing rock; exact lithology cannot be determined from the photograph

Clear gemstone earring (likely cubic zirconia)

Cubic zirconia (synthetic zirconium dioxide, ZrO₂); identification from the image is uncertain

Quartz-rich foliated rock, possibly milky quartz vein material

Likely quartz-rich metamorphic rock; exact identification is uncertain from the image

Basalt Cobble

Aphanitic Mafic Igneous Rock (Basalt)

Asphalt Pavement (with aggregate)

Asphalt concrete

Mixed rock and mineral collection

Unidentified assortment of geological specimens; individual species cannot be determined from the image

Kambaba Jasper

Rhyolite (Volcanic rock) or Stromatolite (debated)

Dyed Crackle Quartz

Silicon Dioxide (SiO2) with synthetic dye

Fired Clay Brick (Anthropic Rock substitute)

Anthropogenic polycrystalline ceramic (predominantly Mullite and Quartz: Al6Si2O13 + SiO2)

Small tan pebble, likely sandstone

Quartz-rich sandstone (tentative identification)

Educational Geologic Collection

Mixed Mineral and Rock Collection (Various compositions)

Possible weathered basalt or slag fragment

Basalt, chiefly plagioclase and pyroxene; identification is uncertain from the image

Weathered stone nodule or concretion

Unidentified lithic concretion; composition cannot be determined from the image

Dyed Dragon Vein Agate

Silicon Dioxide (SiO2) with artificial pigment

Sandstone with Concretions / Liesegang Rings

Arenite with iron oxide banding

Quartz-rich rock fragment

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

Quartz (on matrix)

Quartz (Silicon Dioxide, SiO₂)

Possible basalt or other dark volcanic rock

Undetermined fine-grained mafic volcanic rock; basalt is a possibility

Serpentinite

Serpentinite, a rock composed mainly of serpentine-group minerals (approximately Mg₃Si₂O₅(OH)₄)

Xenolith in Basalt

Mafic Igneous Rock with Felsic Inclusion

Rounded gray-green beach cobble

Unidentified lithic cobble; exact rock type cannot be determined from the image

Blue Impression Jasper beads

Impression jasper (microcrystalline quartz/chalcedony), chiefly SiO₂, with iron-oxide and other mineral inclusions

Obsidian

Obsidian (volcanic glass, amorphous silica rich rock)

Cullet Glass (Industrial Slag Glass)

Amorphous Silica (SiO2) with metallic oxide impurities

Small rounded pebble, likely basalt

Fine-grained mafic volcanic rock (likely basalt); image alone cannot confirm composition

Small dark rock, possibly basalt or a weathered pebble

Unidentified specimen; basalt is a possible visual match, but the image lacks diagnostic detail

Chondrite Meteorite

Ordinary Chondrite (Undifferentiated Stony Meteorite)

Fluorite on Matrix

Calcium Fluoride (CaF2)

Note: Item is a Synthetic/Man-made Object

Titanium-coated Stainless Steel (Fe-Cr-Ni-Ti)

Sandstone (Micaceous)

Clastic Sedimentary Rock (primarily SiO2 with Mica)

Terracotta (Man-made ceramic brick fragment)

Baked clay / High-iron ceramic (Silicate-based ceramic)