The Blue Diamond mine, located in the central Nevada Papoose area, opened in the late 1950's and was mined up to 1980. This mine is considered a hat mine, of which there are very few. A hat mine is a small deposit of turquoise that, 'you can cover with your hat.'

The stones that this mine produces, which are usually large pieces in plate form, looks a great deal like Stormy Mountain turquoise because of its black smokey matrix. This stone features dark smoky swirls with brilliant blue windows with the characteristic black chert, which is ever-present in the stone.
A Rare deep blue Turquoise producing mine in Nevada, Blue Diamond was mined mostly in the 60s and 70s. You don't see much of this great stuff around anymore.
It is dark blue with a black matrix of dendrites and triangle shaped black chert. The blue of Diamond Blue is often times a swirling of two dark blues . . . it is stunning . . . when it can be found.  
This mine is now closed and buried under thousands of tons of rock.  A definite collector’s item!