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Dugway Geode
Thunderegg
Other Names:
Thunderegg
Pronunciation:
Dug-way
Type:
Volcanic Rhyolite
Classification:
Rhyolitic thunderegg, Volcanic Nodule\
Chemical Formula/Composition:
silica dioxide (SiO2), and Potassium Oxide (K2O)
Luster:
exterior is dull, interior glassy
Color:
dull brownish-gray exterior, interior shades of white, gray, light blue, purple or pink
Transparency:
exterior opaque, interior translucent
Mohs Hardness:
6.5 - 7
Fracture/Cleavage:
conchoidal fracture
Uses:
Decorative display, jewelry making
Key Features:
cavities lined with white, clear, or amethyst quartz, alongside banded agate, typically ranging from 2 to 4 inches in size.
Sources:
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