Mineraloid (Man Made)

Natural White Pearl

Calcium Carbonate (Aragonite/Calcite) with Conchiolin - CaCO3

Pearl (Biogenic Mineral)

Calcium Carbonate (primarily Aragonite) with Conchiolin; CaCO3

Mahogany Obsidian

Volcanic glass (SiO2 with Hematite or Magnetite inclusions)

Fossiliferous Limestone

Limestone (composed primarily of calcite with included fossils CaCO3)

Amber

Succinite (fossilized tree resin)

Amber

Succinate (Fossilized Tree Resin)

Coquina

Bioclastic Limestone

Yellow amber beads

Amber (fossilized tree resin; organic mineraloid, not a true mineral)

Tumbled black stone, likely obsidian

Obsidian — volcanic glass, chiefly silica-rich rhyolitic composition

Blue glass-like bead or gemstone keychain ornament

Indeterminate; likely cobalt-blue glass or synthetic blue spinel, not identifiable as a natural mineral from the image

Chert

Chert (Microcrystalline Quartz)

Greenstone, likely serpentinite

Serpentinite; predominantly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chlorite, and talc

Potassium feldspar

Orthoclase or microcline; KAlSi₃O₈

Diamond (Cut Gemstone)

Carbon (C)

Granite

Granite (a common rock name, not a single mineral species, composed primarily of quartz, feldspar, and mica/amphibole)

Sandstone

Arenite (mostly SiO2)

Tumbled chert or jasper pebble

Microcrystalline quartz (SiO₂), likely chert/jasper

Sandstone

Arenite (with iron oxide cement)

Calligraphy Stone

Mariam Jasper (Fossiliferous Limestone composed of Hematite and Shell remains)

Mahogany Obsidian

Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)

Diamond

Diamond (pure Carbon, C)

Gypsum (Satin Spar / Alabaster variety)

Calcium Sulfate Dihydrate (CaSO4·2H2O)

Diamond

Carbon (C)

Limestone Pebble

Sedimentary Calcium Carbonate (CaCO3)

Quartzite

Metamorphic Quartzite (SiO2)

Quartzite

Metamorphic Quartz Rock (SiO2)

Exposed aggregate concrete (stone-chip surface)

Portland-cement concrete containing natural aggregate; not a natural rock

Black obsidian

Volcanic glass; predominantly rhyolitic silica glass (approximately 70–80% SiO₂)

Tumbled green-brown stone, likely serpentine

Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite

Tumbled greenstone (probable serpentinite)

Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with chlorite, magnetite, or talc

Tiny rounded brown mineral grain

Indeterminate; possibly iron oxide, garnet, or a weathered sulfide grain

Sandstone

Arenite (SiO2 primarily)

Chalk

Carbonate rock (mainly CaCO3)

Diamond (in Jewelry)

Carbon (C)

Weathered iron-rich sandstone or ironstone cobble

Ferruginous sandstone/ironstone, chiefly quartz (SiO₂) cemented or stained by iron oxides and hydroxides

Sandstone

Arenite (SiO2 composition dominant)

Weathered concrete or cementitious slab (not natural rock)

Artificial calcium-silicate cement composite; likely Portland cement concrete

Tumbled quartz-rich pebble

Microcrystalline quartz (SiO₂), possibly milky quartz or quartzite

Blue-green chrysocolla rough specimen

Chrysocolla, hydrated copper aluminosilicate; commonly associated with malachite, quartz, and limonite

Quartzite

Metamorphic Quartzite (SiO2)

Polished/tumbled brown-and-white mineral fragment

Indeterminate; possibly quartz-rich jasper, brecciated jasper, or an iron-stained quartz mineral

Diamond

Native Carbon (C)