Mellite Value, Price, and Jewelry Information


MELLITE: Germany (0.42). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Mellite is one of the most unusual of all gems, being an organic material formed by inorganic processes, just the reverse of the situation with pearls and coral. Crystals are additionally unusual in being pyroelectric (they generate an electric current when heated). Mellite is soft and very fragile. but is quite beautiful when cut. Truly this is one of the most interesting of the rare gemstones.

Mellite Value

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Mellite Information

DataValue
NameMellite
Crystallography Tetragonal. Crystals prismatic, pyramidal; granular, nodular, massive.
Colors Honey yellow, reddish, brownish, rarely white.
Luster Resinous to vitreous.
Fracture Conchoidal; sectile.
Hardness 2-2.5.
Specific Gravity 1.58-1.64.
Birefringence 0.028-0.032.
Cleavage Indistinct.
Stone SizesMellites are always small (1-3 carats) and may be quite transparent.
Luminescence Dull white in SW, or medium light blue. Medium light blue in LW (Germany) or lemon yellow. May be weak brown in SW (USSR).
Spectral Not diagnostic.
FormulaAl2C6(COO)6 ·18H2O (aluminum mellitate).
Pleochroism Weak; yellow/yellow-brown.

Optics: o=1.539—1.541; e=1.509—1.511.

Uniaxial (-).

Sometimes anomalously biaxial.

Occurrence: A secondary mineral in brown coals and lignites.

Artern and Bitterfeld, Germany; Paris Basin, France;

Czechoslovakia; Tula, USSR.

Comments: Mellite is one of the most unusual of all gems, being an organic material formed by inorganic processes, just the reverse of the situation with pearls and coral. Crystals are additionally unusual in being pyroelectric (they generate an electric current when heated). Mellite is soft and very fragile. but is quite beautiful when cut. Truly this is one of the most interesting of the rare gemstones.

Name: From the Latin word mel, meaning honey, in allusion to the color.