"

THE  CORUNDUMINIUM
 
  Home  
     
 

YOGO  GULCH

  
 

 

  
     
     
     

YOGO  SAPPHIRES:   MINE  UPDATE

 

Pictures are thumbnails - click on one for full resolution picture.

      Yogo Gulch, Montana was, in the early 20th Century, Americas premier gemstone locality, internationally regarded for its small but gemologically superb "cornflower blue" sapphires.   Unfortunately, virtually all ventures on the property have shut down, leaving one "mom and pop" underground operation and a few "Sapphire Villagers" to extract stones from hand-dug dike material.   

     Photos above:  The crystal on the left is a 6.62 carat doubly terminated flawless gem, considered to be one of the finest specimens the mine ever produced.  It was found in the early 1980's by Vortex Mining.  Next to it is a nearly spherical "pea", flawless and weighing 6.16 carats - the best Yogo "cutter" I have seen.  It was found by Paul Davis around 1990.

     Cut stones over one carat are relatively uncommon, but in the right photo the pentagon in the pendant is 3.20 carats and the pear is 3.60 carats.  The pentagon was found by Paul Davis, who had it cut and mounted in Great Falls.  Randy Gneiting (one of the Villagers) found and cut the pear. 

     These are in our collection.  The pear and the 6.62 ct. crystal were pictured in the Mineralogical Record Supplement on Private Texas Collections, January, 2009. 

     A small percentage of the stones are purple to violet; but these are almost always small, or fragments.  My two favorite exceptions are shown here.  The "triangulated" crystal on the left (about 3.4 carats) came from Vortex Mining, and the one (actually a saturated red wine violet) on the right was found by Vortex Mining's reincarnation, Yogo Creek Mining, a few years later.  Fortunately, neither was cut before we got our mitts on them!  
     (Left)  I am indebted to Amos Knapstad, long-time friend and owner of the only other collection of Yogo sapphires that I would kill for.  It was he who arranged the deal for the second violet stone.  As a Villager and later beankeeper for Yogo Creek Mining, he assembled his own outstanding collection.   After the Tucson Gem and Mineral Show in 2007, Amos donated the crystal on the left to our collection, which weighs about 3 carats.  In August, 2010, he further secured his safety with a 4.04 ct. tabular crystal made unique by the large violet center, actually a hex phantom (right two images)!           
     There are two properties ("Roncor" and "Vortex") which include just about all of the known mineralization.  Mining will not be easy, even if unification takes place, as the surface reserves are pretty well depleted and the underground ore body (mostly dike material) is not very thick and at depth is much harder. 

     The first image on the left is of the old British hydraulicking cut near the Gadsden House, and the second is of the dike about 250 feet below the surface - note the purple and yellow primary ore!

     (Right)  A few years ago, we washed some "waste rock" from an access drift, but to our surprise it turned out pretty hot.  That's me, holding two gem crystals over 6 carats each, found in the top riffle of the jig!

      

    Update after Tucson, February, 2007:  Discussions requested with Roncor did not take place, and it is not clear whether there is any interest with them in either selling or redeveloping their mine.  We abandoned plans to unify the properties and mine them. 
    In August, 2008, meetings were held at Sapphire Village with Mike Roberts (Roberts Yogo Company), who had recently acquired and consolidated virtually all of the unpatented interests (the Vortex claims).  He is very knowledgeable (having extensive experience mining gold in northern Alaska) and is successfully extracting stones from deep ore reserves.  This drill and blast underground operation is ongoing, so rumors of the death of this mine are somewhat exaggerated.  (10/29/2010)