anhydrite

["Stacy Shure" <shurefamily@xxxxxxxxxxxxx>]

Hi Justin:

I carve anhydrite on a regular basis.  What you need to remember from the
start is that the composition of anhydrite is the same as for marble -
except it has absolutely no water in it.  Having said that, you need to
protect this stone from water.  Water degrades the stone.  When wet
polishing the stone you have to do so very cautiously.

Anhydrite is very hard, and can be very fragile.  Pnuematic chisels are
therefore not recommended, unless you dial down the air pressure and use no
more pressure than you would for a soft alabaster.  Anhydrite can crack and
fracture so the vibrations must be kept to a minimum.

Riflers will work although it is probably more useful to use a good grinder
on this stone.   I use zec pads, silicone carbide and diamond bits on it.  I
then polish it only to 600 at the most.  The stone does not take much to
polish it, and you have to be careful to not produce too high a gloss.

You should also seal the finished piece.  White anhydrite in particular
picks up grease and grime very easily and will show it, too.  I recommend
511 sealer (you can now buy it economically at any home depot).

Just curious - where did you purchase this stone?  I know Randy at Neolithic
Stone in Vancouver, B.C. sells a good quality stone and also sometimes has
blue anhydrite/blue marble.

Best of luck!

Stacy Shure
Los Angeles, Ca.