[ Top ] [ Japanese ]

Howieite [abbr. Hw ]

Year of discovery: 1964 (Laytonville quarry, USA), 1979 (Japan)

Locality list: 14 localities of howieite

• NaFe₁₂Si₁₂O₃₁(OH)₁₃
• Na(Fe²⁺,Mn)₁₀(Fe³⁺,Al)₂Si₁₂O₃₁(O,OH)₁₃
• [Na⁺][Fe²⁺₁₀][Fe³⁺₂][(OH)₁₃|Si₁₂O₃₁]^27-

• Class: Howieite group
• Class: Inosilicate (Single chain) - Hydroxide

• Fe => Mn: Taneyamalite

• Color: Dark green, Black
• Streak: Grayish black
• Luster: Greasy
• Diaphaneity: Transparent-Translucent

• Cleavage: Good on {010} (1 plane), Distinct on {100} (1 plane), Poor on {210} (1 plane)
• Density: 3.4

• System: Triclinic
• Group: 1, P1
• Lattice: a=10.2, b=9.7, c=9.6, α=91.3, β=70.7, γ=109.0