Bicchulite

Bicchulite
Sharp, gray, rectangular crystals to 4 mm of bicchulite pseudomorphs after gehlenite crystals richly cover the quartz-rich matrix
General
Category	Silicate mineral
Formula (repeating unit)	Ca2(Al2SiO6)(OH)2
IMA symbol	Bch[1]
Strunz classification	9.FB.10
Crystal system	Cubic
Crystal class	Hextetrahedral (43m) H-M symbol: (4 3m)
Space group	I43m
Identification
Color	White or grey, colorless in thin sections
Cleavage	Indistinct
Mohs scale hardness	2.5
Luster	Earthy, powdery
Streak	White
Diaphaneity	Semitransparent
Specific gravity	2.813 (synthetic)
References	[2][3][4][5]

Bicchulite has an ideal chemical formula of 2CaO•Al₂O₂•SiO₂•H₂O, which was formularized from the hydrothermal synthesis of synthetic gehlenite (2CaO•Al₂O₃•SiO₂). Also, bicchulite was sighted in the mines of Japan with related minerals. This sodalite-type structured bicchulite has an uncommon ratio of aluminium to silicon, causing difficulties deciphering the structure. Because of bicchulite's structure it has a powdery texture, which leads to complications in obtaining information on the mineral's physical properties. Despite this problem, the color, specific gravity, and crystal size of bicchulite are known. Although bicchulite was only discovered about 40 years ago, technology has been rapidly advancing, allowing more accurate results to be made from experiments done today.