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Techniques for CollectorsJust a tip about polishing Selenite.

14th Jan 2011 23:58 GMTBri Dragonne

I had a cleaved section of Selenite with Copper dendrite inclusions that I needed to polish recently so I could show the inclusions.


Please, do NOT use this technique on your fave specimen! It worked for me but I take no responsibility, etc etc. :)


The section had been cleaved and was shiny at one time, but over various handlings, it had become rather scratched.


So, several compounds and no luck later, I remembered that Selenite dissolves in water...


I then ran hot water from the tap over it (Slowly heating the water so that it didn't get shocked, the specimen I mean) and then cooling the water and flinging the excess off.


I ran the water over it for about 15 minutes and amazingly, there was a super shiny finish with interesting patterns on it.


This is just a tip for if anyone else does a search like 'How to polish Selenite' :)


-Bri

15th Jan 2011 18:47 GMTJohn Truax

Brilliant Bri!

15th Jan 2011 22:47 GMTMatt Neuzil Expert

photo? too bad there wont be a before and after would be neat to see

16th Jan 2011 00:46 GMTBri Dragonne

I will scuff it up a bit (Easy to do) and make a before and after photo ;)



-Bri

15th May 2012 16:21 BSTBeth

Not sure if anyone is still checking this thread, but I came upon it looking for a way to restore the polish to a piece of selenite. I had gotten a polished selenite palm stone and in trying to get the stickiness from the price tag off, I used water, dish soap, and when that didn't work, water and goo gone. The process took the polished finish off the entire piece. I was since told you shouldn't use water with selenite, and a rock shop said they could buff it for me (they are kind of out of the way to get to, and it would cost about the same as what I paid for the stone originally.)


I'm a little leary of doing anything more with water since that seemed to have ruined the finish to begin with. Is there a link to the before/after photos? And are there any more specific details such as how long you ran hot water over it before changing to cold water, etc...?


Otherwise, are there any other suggestions out there for polishing selenite.


Thanks much!

15th May 2012 18:37 BSTDonald Slater

I have not tried the hot water polishing but in the past I did some sculptures from selenite. I got a good polish by hand using soft leather and Aluminum oxide polish paste after sanding with 600 grit or finer. I have also used lately ZAM on a soft cotton buff wheel on my polishing motor.

16th May 2012 08:48 BSTRock Currier Expert

How big was the polished piece of selenite. Is it really a crystal of gypsum or of the satin spar variety? It it is not too big you might try putting it in the water reservoir of your toilet for a couple of days.

16th May 2012 10:56 BSTAndrea Sansoni

In my experience washing gypsum crystals with water (even cold for a short time) removes the luster and ruins the specimen, I don't think there is a way to recover it, alcohol is ok.

20th May 2012 14:24 BSTBeth

Thanks everyone.. Note to Rock Currier -- it's a palm sized piece and maybe satin spar-- when it was polished it reminded me of satin. It looks very similar to what is pictured here at the following website, though mine maybe wasn't quite as translucent as the ones pictured: http://www.curiogrove.com/selenite/shs01.htm (I did not get this from this site). It's representative of its size as well. But I also got an e-mail from someone who said that selenite loves water-- just not being submerged in it. It will dissolve if submerged.


I don't have any buffing tools-- and it's sort of sounding like hand buffing won't quite cut it. The stone is still smooth-- just no longer polished.


Thanks all for the comments and suggestions. I will check back periodically to see if anything else is posted...

23rd May 2012 18:58 BSTDonald Slater

I have used a soft cloth or soft leather impregnated with a polish compound usually Aluminum Oxide but Cerium Oxide would do. I think a soft leather of chamois worked better and it does take a little while and a lot of elbow grease although a buffing wheel does a better job. The piece may look smooth but it may be best to sand it with 600 grit and even down to 1000 grit sandpaper first. You might want to start with 1000 grit since it may have be polished previously and just gotten etched. You can usually find really fine grit silicon carbide sand paper at an auto parts store. You have to do it with a little water as well or the sand paper clogs up to fast and it is dusty. Gypsum does dissolve in water but very slowly in cold water. When I use to do gypsum sculptures using mostly satin spar, I would have a pan with a little water in which I set the piece in and dipped the sandpaper in and out of the water as I sanded. This keeps the dust down, the piece clean and the sandpaper doesn't clog up too fast. The piece isn't submerged just setting in the water or held near. The polish is done with a slurry of polish compound.

11th Jun 2012 19:28 BSTAaron Cross

I have a question as well. Yesterday I went with the Colorado Mineral Society to a dig site at the Denver International Airport, who one of the members is the excavation manager so we had permission to collect. I found and dig so much Selenite that it was weighing down my car, I have really clear crystals, a couple giant plates that I chiseled off sand stone boulders, and some large ones completely covered in clay and mud. A lot of the plates have thin crystals cover in mud, I cleaned a couple of really nice small pieces under running water with dish soap. They still show clay and some of the cracks, what would be the best way to clean the big fragile plates without breaking things and getting the rest fully clean?


Thanks Aaron,

11th Jun 2012 21:34 BSTRock Currier Expert

Buy one of the little high pressure fabric guns and this will solve a lot of your cleaning problems. Read the soap and water section of Cleaning Quartz. http://www.mindat.org/article.php/403/Cleaning+Quartz

11th Jun 2012 21:49 BSTEdgars Endzelins

Thanks! I have some interesting satin spars (including ones with celestite cones and wave ripples), unfortunately some of my best pieces, which I collected 14 years ago from locality which is no longer accessible, have got some damages. I will first start with some not so good pieces and maybe make some pictures with results.

11th Jun 2012 22:17 BSTAaron Cross

Awesome, thanks rock! I'll post some pictures when I get them clean because I don't see this location anywhere on here, maybe because it's private property and only people with someone who works there can go and dig?

11th Jun 2012 22:43 BSTEdgars Endzelins

Before and after 30 minutes under running warm tap water. Most of damages are gone, except for some major ones. Specimen looks kinda shiny now.

9th Jun 2014 18:41 BSTAlexa Chihuahua

Hi! i hope you speak/ read spanish. :)


Yo tengo una gran colección de selenita y te puedo decír que trabajo con ellas haciendo muchas figuras, desde colguijes, hasta espadas, y las pulo con una lija gruesa primero, para darle forma y para pulir, uso un par de lijas de agua (negras) 1500 y termino con la 2000. quedan espectaculares!! si puedes ponte en contacto conmigo vía e-mail, te puedo pasar fotos mañana.


Saludos!!

27th Jan 2015 14:47 GMTSanguine

No no, definitely don't do this. Worst case scenario you will end up having to pay for a new toilet. Best case scenarios your crystal will still completely dissolve. Selenite is water soluble. Which is also why it should never be used to make a crystal elixir. You will swallow times sharp selenite splinters, which will usually be passed through unnoticed.... I'd hate to be the exception though

26th Mar 2017 07:51 BSTWilliam Schade

Sanguine, yes selenite does dissolve in water, but only very slowly... I've had a log of selenite about 5 lbs or so sitting in some water in my backyard for the past 3 months... The top is out of the water so as it rains the selenite takes on a very cool effect, and this is also a very natural effect since this could very easily occur in nature. I would put a selenite wand in my toilet tank right now just to prove that in a month, it will still be there, it may weigh slightly less, sure... If it's already a small piece it may weigh a lot less... A tiny enough piece could easily dissolve. A decent sized piece however won't look too much smaller, you'll mostly be distracted by how much shinier it is. Just as river rocks take on that water polish... Well it just works even faster on selenite since it's so soft.
 
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