Abstract
Examination of length-fast chalcedony by transmission electron microscopy reveals significant structural differences between microcrystalline fibrous quartz and ideal α quartz. Individual crystals that make up chalcedony fibers are elongate along [110] and are twisted about the fiber axis. Streaks in electron diffraction patterns of single fibers indicate pervasive disorder among the {101} and possibly the {011} planes, and in dark-field images the texture of this structural disorder appears dendritic. Because the streak systems associated with {101} and with {011} intersect at the expected locations of primary diffractions associated with the mineral "moganite', demonstrations of the presence of "moganite' require complementary characterization techniques, such as X-ray powder diffraction -from Authors
Original language | English (US) |
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Pages (from-to) | 452-460 |
Number of pages | 9 |
Journal | American Mineralogist |
Volume | 79 |
Issue number | 5-6 |
State | Published - 1994 |
All Science Journal Classification (ASJC) codes
- Geophysics
- Geochemistry and Petrology