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GEOREF RECORD

Plumbophyllite, a new species from the Blue Bell claims near Baker, San Bernardino County, California

Anthony R. Kampf, George R. Rossman and Robert M. Housley
Plumbophyllite, a new species from the Blue Bell claims near Baker, San Bernardino County, California
American Mineralogist (August 2009) 94 (8-9): 1198-1204

Abstract

The new mineral plumbophyllite, Pb (sub 2) Si (sub 4) O (sub 10) .H (sub 2) O, orthorhombic with space group Pbcn and cell parameters a=13.2083(4), b=9.7832(3), c=8.6545(2) Aa, V=1118.33(5) Aa (super 3) , and Z=4. It occurs as colorless to pale blue prismatic crystals to 3 mm, with wedge-shaped terminations at the Blue Bell claims, about 11 km west of Baker, San Bernardino County, California. It is found in narrow veins in a highly siliceous hornfels in association with cerussite, chrysocolla, fluorite, goethite, gypsum, mimetite, opal, plumbotsumite, quartz, sepiolite, and wulfenite. The streak is white, the luster is vitreous, the Mohs hardness is about 5, and there is one perfect cleavage, {100}. The measured density is 3.96(5) g/cm (super 3) and the calculated density is 3.940 g/cm (super 3) . Optical properties (589 nm): biaxial(+), alpha =1.674(2), beta =1.684(2), gamma =1.708(2), 2V=66(2) degrees , dispersion r>v (strong); X=b, Y=c, Z=a. Electron microprobe analysis provided PbO 60.25, CuO 0.23, SiO (sub 2) 36.22 wt%, and CHN analysis provided H (sub 2) O 3.29 wt% for a total of 99.99 wt%. Powder IR spectroscopy confirmed the presence of H (sub 2) O and single-crystal IR spectroscopy indicated the H (sub 2) O to be oriented perpendicular to the b axis. Raman spectra were also obtained. The strongest powder X-ray diffraction lines are [d (hkl) I]: 7.88(110)97, 6.63(200)35, 4.90(020)38, 3.623(202)100, 3.166(130)45, 2.938(312/411/222)57, 2.555(132/213)51, and 2.243(521/332)50. The atomic structure (R (sub 1) =2.04%) consists of undulating sheets of silicate tetrahedra between which are located Pb atoms and channels containing H (sub 2) O (and Pb (super 2+) lone-pair electrons). The silicate sheets can be described as consisting of zigzag pyroxene-like (SiO (sub 3) ) (sub n) chains joined laterally into sheets with the unshared tetrahedral apices in successive chains pointed alternately up and down, a configuration also found in pentagonite.


ISSN: 0003-004X
EISSN: 1945-3027
Coden: AMMIAY
Serial Title: American Mineralogist
Serial Volume: 94
Serial Issue: 8-9
Title: Plumbophyllite, a new species from the Blue Bell claims near Baker, San Bernardino County, California
Affiliation: Natural History Museum of Los Angeles County, Mineral Sciences Department, Los Angeles, CA, United States
Pages: 1198-1204
Published: 200908
Text Language: English
Publisher: Mineralogical Society of America, Washington, DC, United States
References: 13
Accession Number: 2009-085396
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 6 tables
N34°00'00" - N35°45'00", W117°40'00" - W114°15'00"
Secondary Affiliation: California Institute of Technology, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, copyright, Mineralogical Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 200946
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