Hematite vs. Onyx — What's the Difference?

Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of Fe2O3.

Onyx primarily refers to the parallel banded variety of the silicate mineral chalcedony. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands: agate has curved bands and onyx has parallel bands.

A black or blackish-red to brick-red mineral, essentially Fe2O3, the chief ore of iron.

A semi-precious variety of agate with different colours in layers

(mineral) An iron ore, mainly peroxide of iron, Fe₂O₃.

A chalcedony that occurs in bands of different colors and is used as a gemstone, especially in cameos and intaglios.

An important ore of iron, the sesquioxide, so called because of the red color of the powder. It occurs in splendent rhombohedral crystals, and in massive and earthy forms; - the last called red ocher. Called also specular iron, oligist iron, rhombohedral iron ore, and bloodstone. See Brown hematite, under Brown.

(mineral) A banded variety of chalcedony, a cryptocrystalline form of quartz.

The principal form of iron ore; consists of ferric oxide in crystalline form; occurs in a red earthy form

A jet-black color, named after the gemstone.

Any of various lycaenid butterflies of the genus Horaga.

Jet-black

Chalcedony in parallel layers of different shades of color. It is used for making cameos, the figure being cut in one layer with the next as a ground.

Same as Mexican onyx.

A deep jet-black color.

Deep, jet-black.

A chalcedony with alternating black and white bands; used in making cameos