 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|||||||||||||||||||||
 |
 |
 |
 |
 |
 |
 |
 |
 |
|
|||||||||||||
 |
 |
 |
 |
 |
 |
|
||||||||||||||||
 |
 |
 |
 |
|
||||||||||||||||||
 |
 |
 |
 |
|
||||||||||||||||||
 |
 |
 |
|
|||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|||||||||||||
|
|
|
|
|
|
|
||||||||||||||||
|
|
|
|
|
||||||||||||||||||
|
|
|
|
|
||||||||||||||||||
|
|
|
|
|||||||||||||||||||
CaZn(AsO4)(OH) Orthorhombic
 |
|
|
 |
|
|
| Figure 25-9. Broken spherules of austinite from Sterling Hill exhibiting splintery fracture among individual acicular crystals. Field of view is 0.4 mm in maximum dimension. | ||
|
Austinite was originally found by Fred Parker and reported from Sterling Hill by Dunn (1979c); it was subsequently found on specimens from Franklin.
Austinite occurs in two habits: as 0.3 mm aggregates of weak-yellow crystals at Franklin and as 0.2 mm, medium-brown spherules and continuous encrustations at Sterling Hill. The spherules have a radial internal texture and break with a splintery surface (Figure 25-9). The density is 4.1 g/cm3, and the index of refraction parallel to the fiber axis is 1.755. X-ray and chemical methods are best for verification.
Austinite is a calcium zinc arsenate hydroxide mineral related to adelite. A microprobe analysis of the spherulitic material is given in Table 25, showing this austinite to have but minor solid solution toward adelite and to be slightly manganoan.
Austinite occurs at Franklin associated with clinochlore and with secondary franklinite and willemite, both in superb crystals. Austinite also occurs rarely at Sterling Hill, as spherules on calcite, associated with kraisslite and hemimorphite.
|
|
|||
|
|
||||
|
||||
| Copyright © 1995 by Pete J. Dunn |
Website
by Herb Yeates
|
|||
|
|
|
|||
|
Link
to homepage
|
||||
|
This
page created: January 11, 2001 |
||||
|
|
|
|||
