I have submitted several messages on this subject and have seen none
of the posted. Don’t know what happened.
Benitoite is found primarily in the Clear Creek area of San Benito
County, California. It is a deep blue to blue-purple stone. It is
found with several other rare mineral species.
I have had the privilege of digging on the Junilla Claim in this area.
There is actually a layer of very ugly Massive Benitoite on this
claim. It glows really great in the light of a UV lamp. We spent
quite an eveinig and night looking for stuff with the light.
Bentonite, as has been mentioned, is a clay resulting from the
breakdown of certain volcanic ashes. It is high silica and I have some
potter friends who have made some interesting slip glazes from the
native materials. That is , bentonite and all of the imputities found
in it in the desert areas of California. It has its primary use as a
drilling mud. It is very hygroscopic, in that it absorbs a great deal
of watter per volume of clay. It is expansible, hence the cracks when
it drys. It is used to help weight down the column of materials in
the drill string to keep the gases from blowing out. It is often
mixed with various barium solutions and other heavy elements to
achieve this end.
Benitoite is possibly the rarest of gem stones.