Cyclosilicate mineral

Properties

Chemical formula

Na₁₁Ca₉(Fe³⁺,Fe²⁺)₂Zr₃Nb[Si₂₅O₇₃](OH,H₂O,Cl,O)₅

Group

Silicates

Crystal system

Trigonal

Hardness (Mohs)

—

Color

Brown

Luster

—

Streak

—

Density

—

Cleavage

—

Fracture

—

Tenacity

—

Crystal habit

—

Transparency

—

Space group

R3m

Fluorescence

—

Magnetism

—

Radioactivity

—

Refractive index

—

Optical character

—

Birefringence

—

Pleochroism

—

Strunz classification

9.CO.10

Dana classification

—

IMA status

Approved mineral and/or valid name (A)

IMA symbol

Fek

Locality

🇷🇺 Kovdor phlogopite mine

Type locality

—

Discovery year

—

Source: Wikidata