Wakefieldite

Formula: (Ce²⁺,Pb²⁺,Pb⁴⁺,Y)VO₄

Origin of name: after locality St.-Pierre-de-Wakefield, Quebec, Canada

Crystal system: Tetragonal

Crystal class: 4/m 2/m 2/m

Twinning:

Unit cell: a = 7.35 , c = 6.56  (Ce), a = 7.105, c = 6.29 (Y)

Colour: Black, dark red (Ce), Yellow, light brown, light yellow brown (Y)

Diaphaneity: Translucent

Luster: 

Habit: crystals to 1 mm, square, prismatic

Hardness: about 4.5-5

Specific gravity: 4.30 (Ce), 4.21 (Y)

Cleavage: None

Tenacity: 

Streak: Rust-brown (Ce), white (Y)

Synonyms/varieties: kusuite [wakefieldite-(Ce)]

Comments: two distinct species with the extensions -(Ce) and -(Y) indicating the predominant rare earth cation in the formula