Best viewed using Adobe Flash Player (8 or higher).
Download hereGENERAL DESCRIPTION
Beryllonite, whose name indicates the presence of beryllium (Be), is a rare beryllium and sodium phosphate, exclusively of pegmatitic origin. It is known only in a few deposits in the world. The crystals are colourless with white, they can be prismatic pseudo-hexagonal, sometimes centimetric but generally they form compact masses. It is possible to use beryllonite as a gem.
However, its lack of colour and its relatively average hardness do not enable him to be a commonly cut gem. The gemmy crystals often come from the pegmatites of Stoneham in Maine (USA), this deposit having produced some stones that could be cut. The largest crystals were discovered in Paprok in Afghanistan. The size of the crystals reaches up to 15 cm.
The type is kept at the University of Yale, Connecticut, USA.
HISTORY : Name given after beryllium, first discovered in this mineral
Species first described in 1888 by Edward Salisbury Dana (1849-1935), american.geologist and mineralogist. The first sample was discovered in 1886 by Sumner Andrews
Type-locality : Mont Mac Kean, Stoneham, comté d’Oxford, Maine, USA
CHEMICAL FORMULA : Na Be (PO4)
CRYSTAL SYSTEM : Monoclinic
COLOR : Colorless, white, pale yellow
DIAPHANIETY : Transparent to translucent
LUSTER : Vitreous to pearly
STREAK : White
MORPHOLOGIE : Small prismatic crystals, fibrous aggregates and massive
HARDNESS : 5,5-6,0
CHEMICAL CLASS: 2,805
DENSITY : VII - Phosphates, arsenates and vanadates
GROUP : Berlinite - Beryllonite - Hurlbutite series
STRUNZ CLASS BEFORE 2001 : 7/A.01-30
STRUNZ CLASS AFTER 2001 : 8.AA.10
