Hunting Pegmatites, Then Smashing Them

I'm headed out to explore some pegmatites tomorrow. Unfortunately I lost my rock hammer out in the desert the other week. So I decided to upgrade!

While this isn't an exact replacement for my smaller rock hammer, it will help me out a lot in my pegmatite hunt tomorrow.

Pegmatites are igneous rocks consisting of crystals about 1" and larger. The usual make up of Pegs are quartz, feldspar and mica. In Southern California they often hold the precious & semi-precious gemstones beryl, tourmaline, topaz, spodumene, garnet and spinel to name a few. Basically a granite with huge crystals.

A small rubellite tourmaline from a pegmatite.

Since a pegmatite is like a granite it's hard, most rocks are though right. So that 4lb sledge with a chisel side is going to come in handy when I need to break some boulders up like these.

(Black tourmaline "schorl" in quartz)

(Pegmatite vein)

And with some luck I will find my way into a pocket like this!

Not likely though as you have to do serious underground mining to find something like that.

Anyway, the area I am going to be hunting is here:

It's part of an old, large quarry complex that produced a lot of beautiful specimens. The host rock is limestone and granite with pegmatite dykes running throughout.

A dyke is an portion of rock that is different than it's host rock. Basically it "Dykes" the rock meaning it blocks one part of the rock from the other, dividing it. This is an example of a pegmatite dyke that has weathered.

So wish me luck in finding a portion that has been weathered and will be easy to break apart with the new sledge hammer. I'm thinking of naming the sledge "Perses" after the Greek God of Destruction. We'll see how well it does tomorrow. Until next time....