Wednesday, June 02, 2010

Azurite Mine, La Sal Mountain Range

Geology of the Site:
The minerals of this area occur in a block that was down-thrust on the crest of an anticline. The fault runs for 16 miles along the crest of the anticline. The anticline was formed by swelling of gypsum and salt of the Paradox formation. The swelling deformed the rock into a anticline because the sediment acted like plastic when it was being pushed out of shape by the swelling of the salt and gypsum. The fault is off set by 3800 feet in many places.

The azurite and other copper minerals were deposited by copper rich fluids that came from the intrusive deep below. These fluids would mix with the saline/brine water closer to the surface. The mixing of these fluids caused the copper mineralization to precipitate out in the form or azurite and malachite filling seams, cracks, voids, and as replacement of other minerals like calcite. In a few really rare cases, the copper minerals also replaced human and rodent bones.

Besides azurite and malachite there are many other minerals found in the area. Including aurichalcite, barite, calcite, chalcocite, chalcopyrite, chrysocolla, clinoclase, conichalcite, copper, cornwallite, covellite, cuprite, digenite, djurleite, enargite, goethite, kaolinite, olivenite, psilomelane, pyrite, sphalerite, tennantite, tenorite, tyrolite, wulfenite, and more, some of which are very rare.

Azurite blue berries are very common in this area. They are nodules, usually of solid azurite. Commonly the larger nodules will be mixed with malachite making beautiful specimens. These nodules from from <¼ inch to over 3 inches.
Smaller sizes tend to be solid and have no crystal structure on the outside. Larger ones, over 1 inch, may form hollow cavities with micro azurite crystals on the inside. Nicer specimens will have crystals on the outside.

Many over look the beauty of the malachite which is very abundant. A good cleaning with an ultra sonic cleaner of a mini-pressure washer will do wonders for the malachite and azurite.

Rock & Mineral Magazine; Utah Issue; vol. 68, No. 6, Nov/Dec 1993

We have arranged to take a couple of trips down to this mine!
June 5th, and June 26th.
We are limited to 35 people per a trip.
Call or go online to reserve your spot today, before these trips are full
and this opertunity passes by.
Rockpick Legend Co.
1017 South Main Street
Salt Lake City, UT 84111

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