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Obsidian
in the Black Rock Desert, Millard County 
One
of the many piles of Obsidian that can be found in Black Spring
area. Picture submitted by S Jenson from Farmington Utah.
Geologic information:
Approximately 2.5 million years ago (late Tertiary Period), volcanic
eruptions in the Black Spring area of the Black Rock Desert in western
Utah spewed out the volcanic rocks rhyolite, pumice, and obsidian.
Obsidian is a dark-colored volcanic glass formed
when molten lava cools quickly. It is usually black but colored varieties
range from brown to red. Snowflake obsidian, a black obsidian with
whitish-gray spots (spherulites) of radiating needle-shaped cristobalite
(high-temperature quartz) crystals, is also found in the Black Rock
Desert. Obsidian has been used for arrowheads and primitive cutting tools,
and is presently used for jewelry.
How to get there: From the west edge of
Delta, Utah, travel west on U.S. Highway 6/50 about 4.3 miles to the State
Highway 257 junction. Turn south on highway 257 and travel approximately
43 miles to a BLM sign displaying "Kanosh 26" and a dirt road
heading east. Turn east onto the dirt road and travel about 6 miles to the
sign for Black Spring. Turn right onto the Black Spring dirt road and park
in the open area across from the watering trough.
Where to collect: Walk in any direction and
obsidian can be found on the ground. Most pieces are black and range from
1/2 to 6 inches in diameter, but some reddish-brown and snowflake obsidian
can be found.
Picture
submitted by S Jenson from Farmington Utah.
Useful maps: Richfield 1:100,000-scale
topographic map, Cruz 7.5-minute topographic map, Bureau of Land
Management (BLM) Recreation and Vehicle Guide to Warm Springs Resource
Area map, and Utah highway map.
Topographic maps can be obtained from the Natural
Resources Map & Bookstore, 1594 North Temple, Salt Lake City, UT
84114-6100, (801) 537-3320 or 1-888-UTAH MAP. BLM maps are available from
the BLM Utah Office at 324 South State, Salt Lake City, (801) 539-4001.
Land ownership: Black Spring is on BLM public
lands but school trust land and private land are nearby; School Trust Land
(state land): section 36 of Township (T.) 23 S., Range (R.) 9 W. and
section 2 of T. 24 S., R. 9 W.; private land: most of section 3 of T. 24
S., R. 9 W. (Cudahy Mine).
Precautions, miscellaneous: A
four-wheel-drive vehicle is recommended but not required for travel on
unimproved roads. Do not collect on marked claims. Bring a rock hammer and
protective eyewear if you intend to break pieces of rock. A hat and water
are recommended. Watch for rattlesnakes and cattle. Please carry out your
trash. Have fun collecting!
Updated Information Submitted By Morgan
"Apache
Tears" can be found near Topaz
Mountain. Instead of taking a right off the paved road to get
to Topaz Mountain stay on the paved road. Eventually the road curves to
the right. Immediately after the curve to your left will be a turn
off to a commercial mine, to your right will be a turn off that goes into
the mountains. Both are dirt roads. The paved road will soon turn to dirt.
Park at the mouth of the road on your right. All around are "Apache
Tears" on the ground. The best places to look are on the left side of
the road that goes to the right and down the paved road just as it turns
to dirt on the left. I have found them from 1 mm to 7 cm.
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