Svabite, fluorinated calcium arsenate,
Formula Ca5(AsO4)3F.
Crystal system: Hexagonal.
Hardness: 4.5
Density: 3.7 gms/cm3
Colour: White, yellow, grey or green.
Streak: Not given.
[Fluorescent]
When the mineral fluorapatite Ca5(PO4)3(F,OH) occurs near arsenic-bearing ores, the phosphate ion is often replaced by an arsenate ion. when the percentage of arsenate ion exceeds that of the phosphate ion the mineral is called svabite. Svabite from Langban, Sweden fluoresces yellow under short wave ultraviolet radiation. Svabite from Franklin, New Jersey is reported to fluoresce a dull orange-brown.
This specimen of svabite is reportedly from Langban, Wermland, Sweden and is shown fluorescing under short wave ultraviolet radiation. Its orange-brown fluorescence is barely visible in daylight and is more characteristic of svabite from Franklin.