Herderite

Herderite is a phosphate mineral belonging according to the apatite, phosphate group, along with components CaBe(PO₄)(F, OH). It forms monoclinic crystals, often twinned then changeable of colour out of colourless via pale yellow after green. It forms a collection including the extra common hydroxylherderite, which has extra hydroxyl ion than fluoride. Herderite which comes from the category of Phosphate mineral with the formula of CaBe(PO₄)(F, OH).  It is a phosphate that is a very rare gem. And it is a gem that will attract too soft for jewelry ware. It is situated in many colors; yellow, green, blue, red, pale violet and colorless. Currently, a product that is most is from Brazil, although it really is present in several localities across the world including pale yellow crystals from Maine, USA. Probably the most notable occurrences of gem quality crystals are Minas Gerais, Brazil and Skardu District, Baltistan, Northern Areas, Pakistan.

Category:	Phosphate mineral
Formula:	CaBe(PO4)(F,OH)
Crystallography:	Monoclinic – Prismatic
Crystal Habit:	Stout prismatic crystals, thick tabular. Commonly pseudo-orthorhombic in aspect, rarely monoclinic; pseudo-hexagonal at times. Also occurs as botryoidal or spheroidal aggregates with a radial-fibrous structure.
Twinning:	On [100] or [001] as fishtail contact. Most crystals are twinned; however, some exhibit no outward signs of this morphology.

 

Cleavage:	Imperfect, Fair; [110] Interrupted
Fracture:	Sub-Conchoidal
Tenacity:	Brittle
Hardness (Mohs):	5.0 – 5.5
Density:	2.95 – 3.02 (g/cm3)
Luminescence:	Fluoresces violet under UV; cathodoluminesces and phosphoresces pinkish orange under X-rays.
Radioactivity:	Not Radioactive

 

Color:	Colorless, pale Yellow, Yellowish Green, light Green
Transparency:	Transparent to Translucent
Luster:	Vitreous
Refractive Index:	1.556 – 1.620  Biaxial ( – )
Birefringence:	0.033
Dispersion:	Moderate; r > v; 0.017
Pleochroism:	Non