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Sunstones
at Sunstone Knoll,
Millard County
Geologic
information: Sunstone Knoll is formed of volcanic vents that
erupted during the early Pleistocene (1.6 million years to about
750,000 years ago). These eruptions left deposits of basaltic
lava and volcanic breccia (angular, broken rock fragments held
together in a matrix of finer grained material). Sunstone is a
transparent, yellowish labradorite (a plagioclase feldspar mineral)
found as crystals in these volcanic rocks and on the flats surrounding
the knoll.
Where to collect: Sunstones litter the ground on the
east side of the knoll. Many small stones can easily be found
when they glitter in the sunlight. Stones range from 1/8 to nearly
1 inch long, but the larger stones are rare. Crystals and fractured
grains of sunstone can also be found in cavities in the lava although
the rocks generally have to be broken to expose the crystals.
How
to get there: From the west edge of the town of Delta (railroad
overpass), 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 13.4 miles (just before mile-marker 56).
A sign on the west side of the road marks the entrance to Sunstone
Knoll on the east. Turn east onto the dirt road, cross the railroad
tracks (watch for trains), and circle around the knoll to the
east side. Please sign the register at the entrance. A private
claim is on part of this site, but individuals are generously
allowed to collect.
Useful
maps: Utah highway map, Delta 1:100,000-scale topographic
map, and Sunstone Knoll topographic map (7.5 minute). 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.
Land ownership: Private mining claim and BLM public lands.
Precautions, miscellaneous: Children should have an easy
time collecting on the flats, but be careful, as glass from broken
bottles can easily be mistaken for glittering sunstone. Watch
for rattlesnakes. Look for trains before crossing the railroad
tracks. A hat and water are recommended. Bring a rock hammer and
protective eyewear if you intend to break open the rocks. Please
carry out your trash. Have fun collecting!
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