Last Thursday myself and a fellow club member went up to a dig site on Winchester Creek, Pend Oreille Co.. We had heard of this deposit from another club member and since neither of us had any beryl in our collection we thought we would give it a go.
Winchester Creek is south of the well known beryl bearing pegmatite on Calispel Peak(see Mindat.org). I surmise that the pegmatites on Winchester Cr. are part of the same general pegmatite formation. I'm sure that with more searching other outcrops could be found in the future.
This outcropping has a dike approximately 2-4' across where exposed. It intrudes a weathered muscovite-biotite granodiorite from the "Phillips Lake Granodiorite" formation (Cretaceous). The major part of the dike is covered by approximately 4' of soil. The pegmatite itself is composed mainly of feldspar with quartz and muscovite making up the remaining bulk. Also found in minor amounts are beryl, schorl, garnet and columbite.
I picked up the following little beauty from on top of the shoulder of the road. I think recent rains had exposed it.
The following are a few of the crystals that we found from a full days dig. Most of the crystals are fractured but do have some area's in them that would cut a cab. I'll report back to you on that later when I have had time to try cutting some.
The following is a nice specimen showing beryl crystals in the pegmatite matrix. You can see the large muscovite book on the right side of the crystals. The small dots you see in the white area on the left are garnets.
All said, our trip was a rousing success. We had beautiful weather and found some awesome specimens. What more could a rockhound ask for??? ;-}
P.S. Give me another trip or two and I'll have specimens to share.... ;-}