Hard marble; should I stop now?

[Biomorph]

I just bought a couple of short cores, a foot or so long, two inches diameter, of a dark marble that I believe is Italian verdi. I tried a riffler on it and hardly made a scratch. I see great possibilities, but, rightly or wrongly don't want to commit weeks to nibbling at a beautiful but very difficult material.
I have sculpted a good deal in African wonderstone [bad dust, insanely expensive], alabaster [good carving, but don't like either the veined or the translucent quality in terms ofr conveying shape and volume], marble of medium hardness [about as hard a material as I feel comfortable with], and limestone [a current favorite]. All of this has been entirely with hand tools. I have never used machines on stone, tho I have used an angle grinder carver and Foredom rotary tool on wood.
Should I simply avoid the verdi and pursue more realistic projects or can this stuff be worked with, say, a rotary tool with a carbide [or diamond] burr? I would appreciate some thoughts as to avoidance or, alternatively, the best tools and abraisives? Is dust a bad problem? I have believed that all dust is bad but marble dust is relatively benign. The thoughts of an experienced hand would be valued.

[desertrock]

Pick up a diamond burr kit of 20 to 40 different sized burrs at harbour freight for cheap. Buy a Dremel with a cable attachment and a rotary pen to hold the burrs. On a piece this small you'll be shaping at lightspeed with less risk of breakage.

Mark

[StevenW]

Yup, what Mark say's is true, if you continue on though you might find Dremels and the like are a bit wimpy in terms of longevity and within a half-dozen little pieces they can burn out.

For just a few bucks more really, a 1/4" shank makita die grinder will last a lot longer: This one is 100 bucks and just a little bigger than a pen tool like a foredom or dremel. "Makita GE0600 1/4" Die Grinder"

http://www.amazon.com/Makita-GE0600-4-Inch-Die-Grinder/dp/B00004YOKS


The 1/4 inch diamond bits/burrs are a bit spendier than the one's Mark is talking about though.. Around 20 bucks each.

[manic]

verde- black with green veining, right?
Unless you really want to expand your expertise, I would suggest you stop. Verdi is an incredibly hard marble. Harder than many granites, which use a pulverizing method of carving, not really carving at all. Many of the hand tools are useless for this stone. It sounds like you are familiar with softer stones and found a likeness for them. Little dremel burrs will do little to even scratch the surface. Diamond blades and carbide burrs used with compressed air tools are about the only way to work this stone by todays standards. You will probably ruin many a tool trying to work this stone.:(

[dondougan]

Biomorph,

There are eight or nine green serpentine stones quarried in Italy, almost all of them with verde (green in Italian) in their name. I have worked four of the Italian greens: Verde Alpi, Verde Issori, Verde di Prato, Verde Fraye (samples shown below in respective order).

The only one that is soft and easy to work with hand tools is the Verde de Prato, which unfortunately is no longer quarried (the pieces I've worked were from a couple of broken antique pedestals - Vasari describes working this stone in his 'Lives').

The others definitely call for power tools, and their hardness is roughly twice that of Italian white Carrara marble. If you use power tools and create dust, safety respirators are also called-for because these stones are not true marbles at all -- they contain a good bit of free silica.

I'd suggest saving the cores until you have the appropriate tools, unless of course you want to use the cores as an excuse to buy several hundred dollars worth of new abrasive toys!

Don
www.dondougan.com

[G. Murdoch]

I have diamond files for hand work on hard stone. Randy at Neolithic stone has a large selection, from 12" files down to needle files, if you want to work by hand.

Good luck,

Graham

[Cantab]

I agree with Don - your'e not working with a true marble here at all. On the MOHR scale, all marbles are just slightly harder than limestone (out of which they are formed). Marble, as a result, is the hardest of the soft stones. The silicates in this material transform it completely, and the result may be that you will be carving in the same way jewellers 'carve'.

Dremels - lightweight carving tools, I find. Never meant for sculpting. I cut my name with one..... I use small diamond discs in a die grinder, but I don't carve silicate.

Rifflers, diamond or otherwise - scraping and scratching, not carving. A riffler, like a good chisel, likes to grip. No grip, no positive relationship with the stone.