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MINERALS INDEX
Stilbite |
| H4(Na2,Ca)Al2Si6O18.4H2O |
| Monoclinic |
Forms
a(100), b(010), c(001), m(110), and f(101)
Habit and occurrence
Stilbite was found in clusters of indistinct crystals in cavities of a porous replacement
area in pegmatite. The feldspar has been replaced by epidote, actinolite, and calcite, and
stilbite was one of the last minerals to crystallize in the cavities.
Stilbite was also found in crystals, with tennantite, galena, sphalerite, and actinolite, in the Sterling Hill mine at the 900-foot level. (See page 35.) The stilbite crystals are pale yellow, radially grouped, and the individuals are penetration twins of the form shown in figure 185.
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Figure 185 Interpenetration twin crystal of stilbite, showing the forms c(001) b(010), m(110), and f(101). Sterling Hill. |
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Very similar but smaller crystals were found coating dark-gray limestone in the Sterling Hill mine at the 1,000-foot level. When found they were at first mistaken for epistilbite and were so reported.
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Website
© by Herb Yeates 1997-2001.
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This
page created: January 12, 2001 6:56 PM
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