A component of bog iron ores; a cement in clays, sands, and bone material; an alteration product of triphylite in granite pegmatites.
IMA Status:
Valid Species (Pre-IMA) 1841
Locality:
Many localities are known; some with well-studied material include: in the Hrbek mine, Svata Dobrotiva (St. Benigna), near Beroun, Czech Republic. In Germany, from the Eleonore and Rot
Link to MinDat.org Location Data.
Name Origin:
For its occurrence near Beroun (formerly Beraun), Czech Republic.
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Physical Properties of Beraunite
Cleavage:
{100} Good
Color:
Green, Greenish brown, Gray green, Dark greenish brown, Dark red.
Density:
2.9
Diaphaneity:
Translucent
Habit:
Druse - Crystal growth in a cavity which results in numerous crystal tipped surfaces.
Habit:
Globular - Spherical, or nearly so, rounded forms (e.g. wavellite).
Habit:
Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Hardness:
2 - Gypsum
Luminescence:
Non-fluorescent.
Luster:
Vitreous - Dull
Streak:
green brown
Optical Properties of Beraunite
Gladstone-Dale:
CI meas= -0.031 (Excellent) - where the CI = (1-KPDmeas/KC) CI calc= -0.049 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2779,KPDmeas= 0.2731,KC= 0.2649 Ncalc = 1.76 - 1.77
Chemical Formula: 
