Pegmatite crystal mining

[BlasterJ]

Has anyone tried mining Pegmatite crystals? I found an outcropping of honey-colored crystals in a big area of volcanic rock. I'm thinking about moving a couple of yards of rock with low-energy blasting and seeing where it goes.

 

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[russau]

I believe that blasting the rock will destroy your peg material .Keeping them in as big of a piece will maintain / increase the value and the desirability .

 

[BlasterJ]

I can take it out in large blocks using expanding grout and small pyrotechnic cartridges. It sounds like the big thing is not to break it up. If I am reading the info on this kind of gemstone correctly, the crystals sort of grow in fingers from the outside inward.

 

[gold tramp]

This type rock you will probably just have take your chances at breakage, can't say other wise without seeing the actual formation, crack those blocks with sledge carefully, what kind crystals you finding if you don't mind.
Gt ..

 

[OwenT]

Cool, do you have any pictures? What mineral is the honey-colored crystals? Makes me think topaz perhaps. Are they gemmy or opaque?

I haven't actually found a pegmatite but I've read about them. Good pegmatite crystals will occur growing free in vugs at the center of the body if there is a vug. You are supposed to be able to tell when you are near the center because the crystals grow larger. I'm not sure what your honey-colored crystals are, but if it's a true pegmatite, there are zones of minerals as you go towards the center starting with 'graphic granite' which has large chunks of feldspar and you might see large books of mica as well. Around the vug is the quartz zone and black tourmaline might start to appear. In the center of the pegmatite will be the quartz crystals, tourmaline, and beryl. To limit the amount of damage to crystals, you'd want to just break open a hole on one side of it and then try to reach in with bars and chisels to pop the crystals off the walls as well as cleaning out any 'floaters' that might have grown in the clay in the center of the vug. Vugs are usually oblong shaped.

There's a rocks and gems forum on Tnet with a few knowledgable people and mindat has a lot of people that know a lot about pegmatites.

 

[smokeythecat]

Honey colored HEXAGONAL crystals in a pegmatite are probably beryl.

 

[BlasterJ]

The crystals I picked up on the surface are 1-4cm in size and appear to be translucent. They were embedded in rock and fractured already, so hard to tell what their original shape was. They were found in layers of colored of rock that looks to be a distinct dike or still and is different than the country rock. They are hard enough to scratch glass and translucent. Pictures are below:

 

[OwenT]

It appears you have just found some colored chalcedony aka amorphous quartz. Looks like the rock might be a basalt. This is very common.

At best you might find a seam of more colorful chalcedony (agate) but I wouldn't get excited over any of that.

Pegmatites occur in intrusive bodies e.g. granite.

No crystals here, keep an eye out though.

 

[BlasterJ]

Sounds good. I might extract a bit so that the kids can have fun mining something. Will post an update. Geologist friend also agrees the rock looks wrong for pegmatites.

It appears you have just found some colored chalcedony aka amorphous quartz. Looks like the rock might be a basalt. This is very common.

At best you might find a seam of more colorful chalcedony (agate) but I wouldn't get excited over any of that.

Pegmatites occur in intrusive bodies e.g. granite.

No crystals here, keep an eye out though.

 

[gold tramp]

Ive found a couple of these vugs, buckets of crystals and many large ones.
I know of a spot has crystals as big as a fist, one would need some heavy blasting to crack the area so it can be dug into.
Let me know if your interested ...

 

[Clay Diggins]

Interesting. I guess if all you have is a hammer everything looks like a nail.

Mining gems with explosives is a fail. Please don't waste your time or materials destroying gem material with blasting. I've seen beautiful rare deposits entirely destroyed with explosives.

Try starting with a wet diamond ring saw. Do the final trims with a smaller wet tile trim saw. Most of the final extraction will be with plastic chisels and homemade wood tools. Avoid rotary hammers - your pocket will collapse and self destruct before you extract it.

If all of that seems like too much work then you probably aren't cut out to be a gem miner. It is a lot of work and very few pockets actually pay off - but when you hit a good one you will understand why delicacy is so important and why intact quality gems are so valuable. Smashing up a great vug due to impatience or inexperience ruins a lot of gems.

You will still have marketable gems if you take care. Even the most careful pros lose gems. Extracting gem crystals requires patience and experience. It's fun to blow stuff up and there are lots of places to do that for fun. Just leave your blasting materials at home when mining gems.

Heavy Pans

 

[gold tramp]

In hard Rock mining sometimes you have no choice but blast, no worries a good powder monkey knows how to dig with blasting.

Never heard of plastic chisels or wood digging tools for gem or hard Rock mining.

Using power tool is fine around gem stones. Just use common sense when digging.

Guess you all never have actually dug any hardrock, sometimes the rock in the ground can be so freaking hard the only choice is drill n blast.

Have fun with your plastic spoons, this is hard Rock man think about it !!

Couple pics of pocket or vug material, this is how it comes out of the hole.
See if I can dig out a few clusters for a pic
Gt...

Some loose stuff, but still good


2/3rds of this material crystals, most we're double terminated.

 

[BlasterJ]

Nice pics! I don't think the material I have is particularly valuable, so I'm going to give it a go in the next week.

 

[Clay Diggins]

Well I guess you learn something new every day.

Here is a group of Mesolite crystal sprays perched on top of white Chabazite crystal psuedocubes.



A closeup of the crystal group. Those are sub miniature calcite crystals intergrown with the Mesolite Crystal spray. Cute huh?



These are kind of delicate. I actually extracted two of these crystal groups that same day but the other one disappeared into a cloud of fine dust floating in the air when my helper tried to gently blow on the crystal group to dislodge a bit of loose crystal. These things are easier to destroy than dandelion fluff.

Being as these are desirable to collectors of zeolite crystal groupings they have some value. Not true gems but certainly more valuable than any of the quartz group of minerals.

I extracted these crystal vugs from a solid wall of fine grained Andesitic Basalt. By hand. Hella lot tougher rock than granite.

All these years of mining gems and crystals and I never knew my plastic chisels and wood wedges couldn't work hard rock. I guess I've just been lucky. I did things that were impossible out of ignorance. Kinda like Wiley Coyote running in midair until he looks down.

If I had known that a blasting expert could remove these vugs without damaging them I could have saved years of practice on patient meticulous extraction techniques.

Thanks for the education.

 

[BlasterJ]

No, I wouldn't try to blast that. I think I would look at maybe doing a saw-cut around the pocket to provide some relief for prying. That looks a lot different than trying to get small, loose stones out however.