Mellite cut Locality : Csordakúti Mine, Bicske-Csordakút, Bicske-Zsámbéki Basin, Fejér Co., Hungary Size : 9.8x8.2mm — Photo: Didier Descouens · CC BY 4.0
Mellite
'Honeystone' — an organic mineral: hydrated aluminium mellitate, found in lignite seams as honey-yellow crystals.
Intro adapted from Wikipedia (CC BY-SA).
Mellite is an IMA-recognized mineral species in the organic mineral class, with the chemical formula Al₂C₆(COO)₆·16H₂O.
It crystallizes in the tetragonal crystal system.
Key properties: Mohs hardness 2–2.5; specific gravity 1.64; White streak; Resinous to vitreous luster; refractive index 1.525; optically uniaxial.
IMA symbol Mel, grandfathered status — known before the IMA’s founding, named in 1793.
Occurs as an uncommon secondary mineral in brown coal and lignite deposits, aluminum typically derived from clay.
Its name comes from the Greek for honey, in allusion to the color.