Zussmanite - K(Fe,Mg,Mn)13(Si,Al)18O42(OH)14
Zussmanite was described by Agrell et al. (1965) as a new mineral, associated with deerite, in riebeckite-garnet-stilpnomelane metachert from the Franciscan formation of California. It was aamed after Jack Zussman, (Professor of Mineralogy, University of Manchester). Prof. Zussman was one of the authors of the Rock-Forming Minerals book series (W.A. Deer, R.A. Howie and J. Zussman).Optical Properties:
• Form: Tabular crystal.
• Relief: Moderate
• Colours: Pale green.
• Pleochroism: Pale green-colorless.
• Interference colors: Low-medium (yellow-orange).
Pale green Zussmanite crystals. Laytonville quarry, California, USA.
Geology of Laytonville Quarry
Laytonville Quarry (Red Box).
Laytonville Quarry
The Laytonville Quarry is the type locality for the minerals deerite, howieite, and zussmanite (Agrell et al., 1965). Situated 8 km south of Laytonville (Mendocino County, California), is a locality where an unusual variety of minerals has been found in Franciscan glaucophane schists. The rocks exposed in the quarry include both metamorphosed sedimentary and volcanic rocks of the Franciscan Formation (Jurassic and Cretaceous age). The metasedimentary rocks include metachert, metashale, metaironstone, and metalimestone.
The Laytonville quarry contains a series of deep-ocean, subduction related, sediments of varying Fe:Mn, Fe:Al and Fe2+:Fe3+ contents, but all enriched in Fe Mn carbonates. These sediments have a complex metamorphic history that has involved the early development of aegirine and garnet, followed by various phases of secondary mineral growth, all of which required the addition of water to the metamorphic assemblages under high-P, low-T conditions. During the course of an early hydration episode deerite formed within most of the ironstones, and zussmanite in certain Fe-rich, Mn-poor pelites.
At a later, and apparently lower pressure period in the metamorphic history, howieite, riebeckite, stilpnomelane, and a more manganous variety of zussmanite have overtaken much of the earlier mineralogy.
Bibliography
• Wood, R. M. (1980). The iron-rich blueschist-facies minerals 3. Zussmanite and related minerals. Mineralogical magazine, 43(329), 605-614.
• Agrell, S.O.; Bown, M.G.; McKie, D. (1965). Deerite, howieite and zussmanite, three new minerals from the Franciscan of the Laytonville District, Mendocino County, California. American Mineralogist. 50: 278.
• Wood, R. M. (1982): The Laytonville Quarry (Mendocino County California) exotic block: iron-rich blueschist-facies subduction-zone metamorphism. Min. Mag. VOL. 45.
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 2x (Field of view = 7mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 10x (Field of view = 2mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 10x (Field of view = 2mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 10x (Field of view = 2mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 10x (Field of view = 2mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 10x (Field of view = 2mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 10x (Field of view = 2mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 10x (Field of view = 2mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 10x (Field of view = 2mm) |
.jpg) Zussmanite (yellow-orange), quarzt (gray) and stilponomelane in a meta-ironstone from Laytonville quarry, California. XPL image, 10x (Field of view = 2mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 10x (Field of view = 2mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 10x (Field of view = 2mm) |
.jpg) Zussmanite (pale green), quarzt (colorless) and stilponomelane (brown) in a meta-ironstone from Laytonville quarry, California. PPL image, 10x (Field of view = 2mm) |