Clinoptilolite and ferrierite from Agoura, California

W. S. Wise; W. J. Nokleberg; M. Kokinos

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Research Article| June 01, 1969

Clinoptilolite and ferrierite from Agoura, California

W. S. Wise;

W. S. Wise

Geology Department, University of California, Santa Barbara, California 93106.

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W. J. Nokleberg;

W. J. Nokleberg

Geology Department, University of California, Santa Barbara, California 93106.

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M. Kokinos

Geology Department, University of California, Santa Barbara, California 93106.

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Author and Article Information

W. S. Wise

Geology Department, University of California, Santa Barbara, California 93106.

W. J. Nokleberg

Geology Department, University of California, Santa Barbara, California 93106.

M. Kokinos

Geology Department, University of California, Santa Barbara, California 93106.

Publisher: Mineralogical Society of America

Received: 08 Nov 1968

Accepted: 17 Jan 1969

First Online: 06 Jul 2018

Online ISSN: 1945-3027

Print ISSN: 0003-004X

Mineralogical Society of America

American Mineralogist (1969) 54 (5-6): 887–895.

Abstract

Coexisting clinoptilolite and ferrierite occur in cavities in an andesitic breccia near Agoura, Los Angeles County, California. The average cell contents of the clinoptilolite and ferrierite are Na₂₃K_1.7Ca_0.5Mg_0.3Al_0.2(Si₃₀Al₆) O₇₂·24H₂O and Na_1.8K_1.4Mg_0.6(Si_31.6Al_4.4) O₇₂· 18H₂O, respectively. The clinoptilolite is similar in composition to reported analyses, whereas the ferrierite is far richer in Si and alkalis compared to published analyses.

The clinoptilolite crystals display a form, (201), not reported for heulandite. The optic orientation with OP parallel to (010) and Z ∧a=30° to 45° is distinctly different from that of heulandite. Other properties are 2V_z = 32°-48° and β = 1.479. The small fibers (0.01 mm) of ferrierite prevent detailed optical study. Ferrierite cell dimensions and peak intensities may reflect compositional variation.

The earlier precipitation of calcite probably allowed these Si and alkali-rich zeolites to crystallize from water percolating through the breccia.

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