Hopeite
Hopeite is a hydrated zinc phosphate with formula: Zn3(PO4)2·4H2O. It is a rare mineral used mainly as a collectors specimen.
Hopeite crystallizes in the orthorhombic system with prismatic, vitreous white to yellow crystals. It also forms druzy encrustations and reniform masses. It has a Mohs hardness of 3 to 3.5 and a specific gravity of 3.
It was first described in 1822 from Moresnet, Liège Province, Belgium and is named after Scottish chemist, Thomas Charles Hope (1766-1844) of Edinburgh University.
It has been found in Zambia associated with lazulite.
References
Source: adapted by the editor from Wikipedia, the free encyclopedia; from the article "Hopeite". Image Credit.