Mineral Information and Data:

Mellite
Al2C6(COO)6 • 16H2O [CNMNC approved formula]

Named from the Greek μέλ˘ι for "melis" = honey, in allusion to the color.

IMA status : Valid species (Pre-IMA 1793) Grandfathered
CLASSIFICATION 
Dana
(8th edition) :
50.02.01.01  
  (50) Salts of Organic Acids and Hydrocarbons
  (50.02) (Mellitates, Citrates, Cyanates, and Acetates)
  (50.02.01)
  
Nickel-Strunz
(10th edition) :
10.AC.05
  (10) Organic Compounds
  (10.A) Salts of Organic Acids
  (10.AC) Benzine Salts
  
Crystal system: Tetragonal System
Point group (H-M): 4/mmm (or 4/m 2/m 2/m) — ditetragonal-dipyramidal
Unit cell: a = 15.53Å, c = 23.19Å
Crystal Habit: Crystals prismatic or pyramidal, small, rare; massive, fine granular; nodular; coatings
  
Color: Golden brown or brownish, reddish, yellow
Diaphaneity: Transparent to translucent
Luster: Vitreous to resinous
Hardness (Mohs): 2 to 2.5
Measured Density: 1.64 g/cm3
Cleavage: Poor/Indistinct on {023}, indistinct
Tenacity: Slightly sectile.
Fracture: Conchoidal
Streak: White
  
Geologic Setting: An uncommon secondary mineral in brown coal and lignite deposits, aluminum typically derived from clay.
  
Synonyms/varieties: Honey-stone, Mellilite, Xylocryptite
Luminescent Properties: May fluoresce pale yellow to blue under SW and LW UV.
Other Properties: Pyroelectric. Gemstone Extremely Rare.
Comments: Insoluble in water and alcohol but soluble in HNO3.

 

Mellite
Origin: Csordakúti Mine, Fejér Co., Hungary
Sample size: 3.2 x 2.8 x 2.3 cm
Photo: Rob Lavinsky

 

Mellite
Origin: Csordakúti Mine, Fejér Co., Hungary
Sample size: 6.3 x 6.0 x 4.4 cm
Photo: Rob Lavinsky

 

Mellite
Origin: Csordakúti Mine, Bicske-Csordakút, Fejér Co., Hungary
Sample size: 3 x 1.5 x 1 cm
Photo: Tom Loomis

 

Mellite
(zoom-in of above)

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