Photo: David Hospital · CC BY-SA 4.0

Cyclosilicate, mineral

Properties

Chemical formula

(Na,REE)₁₅(Ca,REE)₆(Mn²⁺,Fe²⁺)₃Zr₃Nb[Si₂₅O₇₄]F₂ * 2H₂O

Group

Silicates

Crystal system

Trigonal

Hardness (Mohs)

—

Color

Brown

Luster

—

Streak

White

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

Ktb

Locality

—

Type locality

—

Discovery year

—

Source: Wikidata