MINERALOGICAL RESEARCH COMPANY



 

General physical features of the Fulgurites from Great Sand Sea, Libyan Desert, Southwestern Egypt.

Type I (Light gray, glassy, tubular)

 

OUTSIDE SURFACE:
FORM: Fairly straight down the length of the tube, equidimensional to flattened in cross section, usually with very pronounced, often convoluted ridges.  Some specimens have a few small, natural holes piercing the walls of the fulgurite tubes (with the edges fused), suggesting the presence of extremely intense heat during their formation.  Some specimens cooled fairly slowly, allowing the walls of the tubes to collapse slightly in one direction, producing an oval to flattened cross section.
COLOR: Light smoky gray, to dark charcoal gray.
TEXTURE: Fairly smooth, glassy, with pronounced ridges.
SAND GRANULES: Modest amount, sometimes nonexistent, i.e., the sand granules were mostly fused during formation.
GLASSY INTERIOR:
COLOR: Pale gray, translucent.
TEXTURE: Smooth, glassy.
BUBBLES (GAS
POCKETS) PRESENT:
Numerous, microscopic.


                           


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