In the mid-1970’s I spent a good deal of time working on projects in Central and Southwestern Colorado. Among several areas of interest in the Gunnison area was an exploration project that incorporated much of the Italian Mountain intrusive complex, an area some 15 miles NE of Gunnison. This is one of the premier mineral collecting spots in the western US, one that has been recognized for the unusually fine specimens found there since it was first described by geologists in the 1870’s.

Later discovery of perhaps the only commercially significant North American deposit of gem-grade lazulite adds considerable interest. It is a place of sublime beauty that is seldom visited by mineral collectors because of it’s remoteness, elevation and lack of access for motorized vehicles.

Italian Mountain complex looking west from Italian Creek drainage

This writing will just introduce the reader to the area and the interesting geology and mineralogy there. There is a variety of literature available concerning the general area and the Italian Mountain complex itself. From the collectors point of view, the best reference is a fine article in The Mineralogical Record by Henry Truebe, (March-April, 1984).

Henry spent some time over a period of several years doing thesis work, mining specimens and evaluating the commercial potential for specimens in the area. He identifies and locates all of the significant species found there.

Italian Mountain is located between the Taylor River and Cement Creek drainages and is best approached from the east from a jeep trail that, starting just north of Taylor Reservoir, follows North Italian Creek to the area of the Star Mine in Star Basin. Several mines in this area produced small amounts of lead, zinc and silver from replacement ore bodies in limestone. The ponds in Star Basin are large enough to produce some fine trout for those interested in fishing. From Star Basin the trail turns south, rounding the east end of the long east-west trending ridge that separates Star Basin on the north from Stewart Basin to the south.

Stewart Basin with South Italian Mountain on left and Central Italian Mountain to right.
Vehicle is near the base of the trail that follows the east ridge to summit area.

American Flag Mountain forms a high North-South trending escarpment east of Stewart Basin. A foot trail from the south side of this ridge provides access from the ridge on the east flank of the main peak to the primary collecting area in a saddle at a contact zone just north of and below the 4,078 meter (13,380 foot) summit.

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Author on east ridge. Note colorful brown alteration of sedimentary rocks near summit and the lighter intrusive quartz monzonite porphry to the right.

Access from the head of Cement Creek follows a trail on the ridge northwest of the North Italian Mountain where the lazulite is found and skirts the peak of North Italian Mountain and approaches the summit of (Central) Italian mountain from the north across a talus slope. This is by far the most difficult access and the trail from the east is recommended. Note that the lazulite deposit is located on patented claims and is off limits to collecting without permission from the owners. Truebe located lazulite in several small occurrences around the main peak of Italian Mountain, but none proved to be of commercial interest.
The three peaks of the Italian Mountain intrusive complex are related to three intrusive ingneous stocks, the youngest of which is about 34 million years old and is usually described as a quartz-monzonite-porphyry (QMP). These rocks intrude Paleozoic sedimentary rocks that intrude limestones, dolomites, shales and quartzite. In these reactive rocks adjacent to the contacts with the QMP main stock and related intrusive dikes are developed skarn zones that contain the primary minerals of interest.

Steeply dipping beds of Leadville Limestone northeast of North Italian Mountain at the head of Cement Creek. The lazulite deposit is below and on a ridge to the left.

Italian Mountain summit from saddle to north. Note sedimentary beds and light-colored intrusive dikes and contact.

Looking north from peak to saddle collecting area. Note digging. Light-colored QMP talus and upper Cement Creek in background.

While there are some 80 mineral species described from the area, the most important and accessible to collectors are found in a relatively small area near the summit of Italian Mountain. These include vesuvianite (idocrase), garnet var. grossular, prenite, clinozoisite, epidote, diopside, chabazite and heulandite. Several pits have been opened on contact zones where these minerals have formed in skarns associated with intrusives and shaley sedimentary rocks of the Beldon formation. My favorite spot is in the saddle north of the main peak. Here the the west slope drops sharply some 500 meters to the Cement Creek valley and to the east is a near vertical drop of some 100 meters to a talus slope above Star Basin.

Ponds in Star Basin from saddle area north of main peak of Italian Mountain

In the 1970’s there were some remnant cables attached to the vertical cliffs below this area. Presumably they were used by some of Truebe’s crew to evaluate the contact zones on the cliff face. There are fine vesuvianite crystals here, up to 5-6 cm, although the best are those up to about 2.5 cm both on matrix and as floaters in collapsed pockets.

Vesuvianite, about 1cm, on grossularite-skarn matrix

Larger crystals, particularly those found near the east edge of the saddle area, tend to be corroded and may show unusual silky, fibrous vesuvianite surfaces. In addition, this is an area where there are gemmy grossularite crystals up to (rarely) 2cm.

Heulandite crystals to 3mm from saddle area.