MINERALOGICAL RESEARCH COMPANY




General physical features of the Fulgurites from
 

MONAHANS  SAND  HILLS,

PECOS  PLAINS, NEAR  MONAHANS,

WARD  COUNTY, WEST TEXAS


TYPE I  (Light gray-white, glassy, tubular)

GENERAL INFORMATION ABOUT THE LOCALITY:

The fulgurites from West Texas are found in the sand dunes of the Pecos Plains. The dune field is approximately 70 miles long and 20 miles wide, and stretches in a narrow band from 20 miles northeast of Crane, Texas, to the southeast corner of New Mexico. The dune field runs parallel to an area called the Llano Estacado, Spanish for "staked plains" where the early travelers passing through this area had to mark their way with stakes because of the lack of any geologic features with which to identify their position. The sand in these dunes is composed of very uniform near white Quartz sand, with traces of iron-rich clay. The sand was laid down about 16,000 years ago. These dunes are the highest points in the surrounding area, and are natural targets for lightning strikes. The fulgurites are typically found in the dunes with no vegetation -- far removed from power lines, telephone poles, windmills, etc., and other items which would attract the lightning. The dunes shift as much as 70 feet per year due to the seasonal change of prevailing winds. The erosion of the dunes, due to the shifting winds, exposes the fulgurites.  These specimens are thin-walled and very delicate.  Specimens weighing > 5 grams, and / or measuring in excess of 4 in length are very uncommon.  All specimens are tubular, with both ends open.

OUTSIDE SURFACE:
FORM: The fulgurite specimens in this group are exceptionally attractive, often with pronounced ridges running down the length of the fulgurite tubes. In some specimens the ridges are slightly curved around, while at the same time running lengthwise down the tubes.
COLOR: Light gray, to light gray-tan.
TEXTURE: Rough, with numerous protuberances / ridges.
SAND GRANULES: White to pale tan in color, small to practically nonexistent, i.e., the sand granules were mostly fused during formation.
GLASSY INTERIOR:
COLOR: Colorless, to light smoky gray, to light tan, translucent to opaque.
TEXTURE: Very smooth, glass-like.
BUBBLES (GAS
POCKETS) PRESENT:
Numerous, microscopic.


                           


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