Mineral With Artificial Coating

Amethyst cluster

Quartz, purple variety; silicon dioxide (SiO₂) colored mainly by iron-related defects and irradiation

Limonite / Ironstone

Hydrated Iron Oxide (FeO(OH)·nH2O)

Peacock ore (bornite/chalcopyrite), likely treated

Bornite, Cu₅FeS₄, and/or chalcopyrite, CuFeS₂

Quartz (Iron-Stained)

Silicon Dioxide (SiO2)

Quartz-rich blue mineral specimen, possibly blue quartz or chrysocolla-bearing quartz

Quartz (SiO₂), with unidentified blue secondary mineral or inclusions

Possible iron-oxide concretion with a dark mineral cap

Iron-oxide–cemented sedimentary concretion; exact composition cannot be determined from the image

Iron-stained quartz vein fragment

Quartz (SiO₂), likely with limonite/goethite iron oxides and minor sulfides

Weathered concrete or cementitious slab (not natural rock)

Artificial calcium-silicate cement composite; likely Portland cement concrete

Polished malachite

Malachite, Cu₂CO₃(OH)₂

Tumbled quartz pebble

Quartz (silicon dioxide, SiO₂), likely milky or smoky quartz

Likely tumbled brown stone

Indeterminate; possibly jasper, chert, or iron-stained quartzite

Likely iron-stained quartz pebble

Quartz (SiO₂), possibly coated with iron oxides such as goethite or hematite

Likely iron-stained quartz or quartz-rich rock fragment

Quartz (SiO₂), possibly colored by iron oxides such as goethite or hematite

Likely ironstone pebble

Ironstone, probably goethite/hematite-rich; exact identification is uncertain from the image

Likely raw gold-bearing rock or native gold specimen

Possibly native gold (Au); identification is uncertain from the image

Iron-stained quartz vein rock

Quartz-rich rock with iron-oxide/hydroxide coatings (hematite/goethite); exact host rock undetermined

Chert with Quartz Druzy

Microcrystalline Quartz (SiO2) with Drusy Quartz Coating

Iron-stained milky quartz

Quartz (SiO₂), with iron-oxide staining

Tiny amber-colored crystal or mineral fragment

Indeterminate from image; possibly quartz, citrine, topaz, or iron-stained feldspar

Ferruginous Quartz

Silicon Dioxide (SiO2) with iron oxide inclusions (Limonite/Goethite)

Titanium Coated Kyanite (Aura Kyanite)

Aluminosilicate (Al2SiO5) with a Titanium-Niobium vacuum-deposited coating

Quartz (Iron-stained)

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Purple Dyed Dalmatian Stone

Dyed Peralkaline Trachyte

Likely iron-stained quartz or quartzite fragment

Quartz (SiO₂), possibly ferruginous quartzite; identification is uncertain from the image

Sedimentary Sandstone with Iron Oxide

Ferruginous Sandstone

Dyed Agate Slice

Silicon Dioxide (SiO2)

Quartz geode/drusy quartz cluster

Quartz (SiO₂), with probable feldspar host and minor iron-oxide staining

Ferruginous Quartz

Quartz (Silicon Dioxide, SiO2) with iron oxide inclusions

Likely garnet (rough, iron-rich variety)

Possibly almandine garnet, Fe₃Al₂(SiO₄)₃; image alone cannot confirm identification

Likely rough garnet

Garnet group, possibly almandine (Fe₃Al₂(SiO₄)₃); identification is uncertain from the image

Quartz Druzy on Matrix

Silicon Dioxide (SiO2)

Dyed Agate

Microcrystalline Quartz (SiO2) with artificial pigment

Ironstone with possible iron-oxide staining

Iron-rich limonite/goethite; exact identification requires testing

Vesicular basalt (likely weathered volcanic scoria)

Basaltic scoria; primarily plagioclase, pyroxene, and olivine

Iron-stained quartz-rich rock fragments

Likely quartz (SiO₂) with limonite/goethite iron oxides; possibly quartzite or silicified rock

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, potentially granitic or quartzitic material

Fire Quartz (Hematoid Quartz)

Quartz with Hematite inclusions (SiO2 + Fe2O3)

Red Tiger's Eye

Silicon dioxide with crocidolite inclusions, SiO2

Smoky quartz-bearing rock

Smoky quartz (SiO₂), possibly in a pegmatitic or quartz-rich matrix

Citrine Quartz / Yellow Quartz Pebbles

Silicon Dioxide (SiO2)

Green Banded Agate

Agate (Variety of Chalcedony/Quartz), SiO2

Rounded granitic gneiss or granite cobble

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