#Rocks
I've been slicing very hard quartz geodes dug a couple of years ago
from the idaho border. They're so hard that the slowest rate of
advance of the saw overpressures the blade into the rock and bends it
– the controller switches the advance motor on and off, and regulates
it's on speed, so that it has control to the point where it could
probably cut just about anything you could think of. I use an
infrared sensor/emittor pair positioned above the blade and watch
"through" the exit spray where the blade exits the cut in the rock.
You can directly determine the cut rate by the opacity of the spray;
and the advance rules (which I determined by using a tape recorder
and describing what I was doing when I did a few rocks manually –
what I saw, what I thought that meant, what I did to accomodate the
situation, like that) use the standard triangular center-of-gravity
fuzzy evaluation to come up with the on/off + speed command(s) for
the saw. Works extremely well, almost to the point where it's
anti-climactic.
So much for the rock saw. 🙂
Just as summer was ending, Anne and I were on a roll, so to speak,
collecting huge clusters of crystals from near Fort Peck lake. I'd
been breaking large boulders, say about 3 to 5 feet in diameter,
using a sledge, and inside these we had consistantly been finding
crystals from miniscule to over 6 inches long. One rock, however,
had a snail-like fossil in it, covered in
mother-of-prehistoric-pearl, which was about 2 feet across. It sits in
my "Montana Collection" display case now. 🙂
Here's something else. Ever see a smokey quartz crystal? I've got some
large ones in my collection – as long as two inches. That's rpetty
long for smokey quartz, it doesn't seem to want to grow big. Well, I
now have a _four hundred pound_ well formed single crystal in my
collection. Well, actually, it's in the back of my Geo Tracker,
because I haven't found anyone foolish enough to want to help me lift
it out… heh heh heh. I'm patient though, and besides, it's helps
the little tin box get traction in the snow and starts conversations
pretty well, too. <grin> This thing came from the continental divide,
about 500 miles from here, right by Butte (pronounced "Butt" if
you've ever seen the place, "beaut" if you do it the way they _want_
you to)… anyway, the thing is positively massive, and it's no
question museum quality. Shine a light thru it and it looks like
maple syrup.. all the faces are intact, and there are some
multiple-growth crystal "steps" in a cavity in one side.