Cahnite (Cahnit in German, Cahnita in Spanish, Канит in Russian[2]) is a brittle white or colorless mineral that has perfect cleavage and is usually transparent. It usually forms tetragonal-shaped crystals and it has a hardness of 3 mohs.[3][4] Cahnite was discovered in the year 1921.[2] It was named Cahnite to honor Lazard Cahn (1865–1940), who was a mineral collector and dealer.[3] It is usually found in the Franklin Mine, in Franklin, New Jersey.[4][3] Until the year 2002, when a sample of cahnite was found in Japan, that was the only known place that cahnite was located.[5] The geological environment that it occurs in is in pegmatites cutting a changed zinc orebody.[2][3][4] The chemical formula for cahnite is Ca2B[AsO4](OH)4.[4][6][7] It is made up of 26.91% calcium, 3.63% boron, 25.15% arsenic, 1.35% hydrogen, and 42.96% oxygen. It has a molecular weight of 297.91 grams.[4] Cahnite is not radioactive.[3] Cahnite is associated with these other minerals: willemite, rhodonite, pyrochroite, hedyphane, datolite, and baryte.[2]

Cahnite on rhodonite
Category Borate minerals
(repeating unit)
Strunz classification 6.AC.70
Crystal system Tetragonal
Crystal class Disphenoidal (4)
(same H-M symbol)
Space group I4
Color Colorless to white
Cleavage Perfect
On {110}
Tenacity Brittle
Mohs scale hardness 3
Luster Vitreous
Diaphaneity Transparent
Density 3.156 g/cm3
References [1]


  1. ^ Mineralienatlas
  2. ^ a b c d Mindat data sheet for Cahnite.
  3. ^ a b c d e Mineral Data sheet for Cahnite.
  4. ^ a b c d e Database entry from Mineral Collecting.
  5. ^ Article stating that veins of cahnite were found in Okayama Prefecture. Archived 2012-02-17 at the Wayback Machine.
  6. ^ Database entry for Cahnite from Mincryst.
  7. ^ Database entry for Cahnite from Japanese database.

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