Chris Tucker Minerals and Gemstones
Specializing in minerals and gemstones from Montana

The Summer Storm Claim, Custer County, Idaho
Source of exceptional quartz pseudomorphs after apophyllite.

Typical rolling terrain of the Summer Storm claim.  The altered andesite flow outcrops along the crests of the low ridge tops.

While visiting John Cornish at his Rat's Nest claim in Idaho following the 2006 Denver show, I spent an afternoon at his quartz pseudomorph after apophyllite locality, the Summer Storm claim.  The claim lies a short distance from the more famous Rat's Nest claim and mineralization is confined to the same strata.   (Read about the Rat's Nest claim here) The Summer Storm claim is the source of what is probably the world's finest quartz pseudomorphs after apophyllite; I am not personally aware of any other locality that produces similar material.   Nearly a half century ago, Norm Radford had found a specimen consisting of quartz pseudomorphs after apophyllite in the general area.  Norm could not recall the specifics of the location but provided Lanny Ream with information on the general area.  In the spring of 2001, Lanny chanced upon the locality and a mining claim was located soon thereafter.  Like the Rat's Nest claim, minerals are found in geode-like nodules in an altered andesite flow underlain by volcanic sandstones.   At the Summer Storm, calcite and quartz are the two principal minerals. 


Several generations of calcite occur at the locality, most of which are coated by quartz.  Blocky root beer colored crystals are frequently found entirely encased in later minerals.  Thin platy crystals of calcite often bridge open cavities and are occasionally coated by quartz.  Somewhat odd groups of stacked rhombohedrons are also known form the locality.  Glassy colorless tabular pseudo hexagonal prisms of calcite have also been found.

Stacked simple rhombohedrons of calcite growing on an earlier thin platy crystal of calcite, 6cm across.

Calcite coated by quartz, 8cm tall.

Nearly colorless calcite crystals growing on thin plates of calcite with quartz. 11cm across.

In its usual form, quartz is rather uninteresting at the locality.  It commonly lines cavities and coats earlier minerals.  Quartz has formed pseudomorphs after apophyllite at the locality and they are surely the finest yet known.  Individuals nearly 10cm long line cavities that reach a meter in size.  The pseudomorphs range from those that are complete to partial cavernous crystals.  The surface of the pseudomorphs ranges from being nearly smooth to one which is studded with small quartz crystals.  Sandy granular quartz is often found between the pseudomorphs.  Quartz is the most abundant mineral at the locality and the pseudomorphs it forms are the specimens of interest.

A typical specimen from the Summer Storm claim.  Greyish white pseudomorphs of quartz after apophyllite with dirty granular quartz.

This hillside is full of open quartz lined cavities.  Unfortunately, only small, very ugly quartz crystals are present in the cavities and gives proof of the localized area of interesting minerals.  A lengthy investigation of the cavities did not reveal the slightest indication of potential specimen producing cavities.

Early prospectors visited the area and with all the obvious mineralization, they spent some time looking for economic minerals.  This shallow adit is one of those efforts.

I thought this piece was attractive so I shot a picture of it.  I liked the piece and it came home with me.

All those open cavities make great dens for rattlesnakes.  There were five of them on one slope and as I sat quietly waiting for one to come out form its hole so I might get a photo of it, I glanced to my right and saw this guy getting ready to taste my leg. 




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