I am new to finishing stones and am going to try and tumble about a pound of rough Brazilian emeralds mostly still in their black matrix. I have a couple of questions. Can I use small agates with the emeralds to make up remaining stones to fill the tumbler? and whats grits I should use?"
Hi Marty, The “right” approach to take will depend alot upon the look
you’re hoping to get, as a result. First and foremost, what’s the
capacity of your tumbler, and is it a vertical rotary, diagonal
rotary or vibratory tumbler? (The type of unit will affect the
stones differently; if using a vertical unit, you may want to add in
some plastic pellets with the load, to cushion the stones as they
drop [or “tumble down”] from each rotational cycle.) Next, how do
you want your finished product to appear? If you want to see the
Emeralds look pretty much as they do now, then toss them into your
tumbler with the matrix intact, just as received. If you’d like to
see them matrix-free, you might want to invest in heavy rubber
gloves, a clear poly container (like those made by Rubbermaid) and a
quart of Muriatic acid. Under ideal conditions, you’ll dig a small
hole in the backyard to hold the container, place the Emeralds in
the container (again, outside your house, because those fumes can
be pretty nasty!), pour in enough of the Muriatic to cover them, put
the lid on and come back in 8-24 hours, assuming you’re not
experiencing sub-freezing temperatures, at the time. When you
return, the next day, bring a pail with a gallon or so of water in
it, and gently pour the acid and stones into it. You’ll find that
the Emeralds’ matrices have been dissolved into a brackish muck at
the bottom of the pail, and the green crystals are ready to be
tumbled!
As for the next steps, there are several different options you can
go by, but the easiest way is to pick up a pre-sorted set of
tumbling grit charges, available through (gulp) Rio Grande, TSI and
Alpha Supply, to name but a few. These will have the three or four
different stages of grit you’ll need (with complete instructions),
so all you’ll have to do is follow the steps and enjoy the results!
Hope this has helped!
All the best, Doug Douglas Turet, GJ Lapidary Artist, Designer &
Goldsmith Turet Design P.O. Box 162 Arlington, MA 02476 Tel. (617)
325-5328 eFax (928) 222-0815 anotherbrightidea@hotmail.com