Juonniite Locality: Kovdor Zheleznyi Mine, Kovdor Massif, Kola Peninsula, Murmanskaja Oblast', Northern Region, Russia Dimensions: 30 mm x 30 mm x 10 mm; Field of View: 2,2 mm Collection and photograph Christian Rewitzer. — Photo: Christian Rewitzer · CC BY-SA 3.0
Juonniite
A rare hydrated calcium-magnesium silicate found at Namibia's Kombat mine.
Intro adapted from Wikipedia (CC BY-SA).
Juonniite is an IMA-recognized mineral species in the phosphate class, with the chemical formula CaMgSc(PO₄)₂(OH)·4H₂O.
It crystallizes in the orthorhombic crystal system (space group Pbca). It is a member of the Overite structural group.
Key properties: Mohs hardness 4–4.5; specific gravity 2.43; White streak; Vitreous luster; optically biaxial.
IMA symbol Juo, IMA status: approved, named in 1996.
A rare mineral found in cavities and contacts with ore minerals in a metasomatized carbonatite stockwork.
It is found associated with Dolomite, magnesite, bobierrite, kovdorskite, manasseite, hydrotalcite, apatite, strontiowhitlockite, pyrite, strontian collinsite, rimkorolgite, talc.
The name comes from the Finnish name (Juonni) for the Yona River, in allusion to the locality of first occurrence of the species.