Junitoite Dimension: 3.5 x 3.0 x 1.8 cm Locality: Christmas Mine, Christmas, Christmas area, Banner District, Dripping Spring Mountains, Gila County, Arizona, USA Description: A wealth of vitreous to pearly junitoite crystals to 4mm adorn one end of this specimen. These crystals are about as large as they get. This is a fine example of this rare calcium zinc silicate from the one-time find at the Christmas mine. A significant USA rarity. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Junitoite
A hydrated calcium-zinc sorosilicate discovered in 1976 at Arizona's Christmas mine, named for mineral chemist Jun Ito.
Intro adapted from Wikipedia (CC BY-SA).
Junitoite is an IMA-recognized mineral species in the silicate class, with the chemical formula CaZn₂Si₂O₇·H₂O.
It crystallizes in the orthorhombic crystal system (space group Aba2).
Key properties: Mohs hardness 4.5; specific gravity 3.5; Vitreous luster; refractive index 1.664; optically biaxial.
IMA symbol Jit, IMA status: approved, named in 1975.
Found in a retrogressively altered tactite zone, closely related to the breakdown of sphalerite in the ores.
It is found associated with Kinoite, apophyllite, calcite, xonotlite, smectite.
The name refers to Dr. Jun Ito (1926–1978), Japanese-American mineral chemist, Harvard University, Cambridge, Massachusetts, USA.