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Gadgets, Gizmos, and Dohickeys => Cutting, Grinding, Polishing => Topic started by: treehstn on March 10, 2018, 06:45:06 PM

Title: Cutting & polishing selenite
Post by: treehstn on March 10, 2018, 06:45:06 PM
Hi everyone!

I'm brand new to the forum and new to crystals and rocks.  Been collecting for about 2 years and now selling some also.

I'm very interested in learning how to cut and polish selenite.  I have rough selenite sticks that I'd like to polish so that they are long and squared up on the sides.  And I have small, thin bricks that are already polished but I need to cut them in half length-wise so each one is 1/4" thick instead of 1/2" thick. 

I have not worked with any rocks, minerals or crystals like this so have no idea how to get the job done.  I've searched youtube and the web in general and can't seem to find any instructions or help.  I'm attaching pics of the selenite I'm working with.

Thank you!

Cheryl

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Title: Re: Cutting & polishing selenite
Post by: peruano on March 12, 2018, 05:48:54 AM
You need to find a lapidary person or club.  They could show you how to do either cut or polish in a matter of minutes. Slicing the slab would be easy with a slab saw and the slab glued onto a wooden stub.  I'd bet you are within 30 minutes of someone who can solve your needs. 
Title: Re: Cutting & polishing selenite
Post by: Slabbercabber on March 12, 2018, 06:28:12 AM
Selenite is very soft.  You should be able to polish it with plain sandpaper in increasingly finer grits until you get to polishing compound.  You can do this by hand, dry.
Title: Re: Cutting & polishing selenite
Post by: Jhon P on March 12, 2018, 01:35:02 PM
You may be able to cut it with a hand saw or hawk saw
Title: Re: Cutting & polishing selenite
Post by: VegasJames on October 30, 2018, 11:59:36 PM
First want to point out that what is is in the picture is not selenite. It is satin spar. Selenite is the smaller clear version of gypsum. Satin spar is the translucent fibrous version of gypsum commonly mislabeled as selenite.

I have cabbed a lot of red selenite and some other selenite.  It grows in plates, which makes cutting and cabbing difficult. The trick with actual selenite is to lightly round off the sharp edges as you go so they do not catch the cabbing wheels and split the stone. When finished cabbing I buff the stones with Zam, which gives them a great polish. It is a little hard to photgraph well but here are some examples. The crystal looking one I flat lapped the sides and points:

(https://farm2.staticflickr.com/1860/43262685255_3030f6d2fa_c.jpg) (https://flic.kr/p/28UYz5t)20180820_174624 (https://flic.kr/p/28UYz5t) by James Sloane (https://www.flickr.com/photos/143011703@N05/), on Flickr

And here is an example a friend wire wrapped for me:

(https://farm2.staticflickr.com/1881/44167717341_6cd1149774_c.jpg) (https://flic.kr/p/2ahX6zX)20180820_174915 (https://flic.kr/p/2ahX6zX) by James Sloane (https://www.flickr.com/photos/143011703@N05/), on Flickr

Satin spar should be a lot easier to work with due to the fibrous nature, which will help to hold it together better.

As far as cutting I would use a tile saw with water. Then the pieces can be shaped and again buffed with Zam to bring out a highly polished surface.