FMF - Friends of Minerals Forum, discussion and message board

[Mathias]

Hi, I've acquired a large and old lump of Schalenblende from the Plobieres/Vieille Montagne region in Belgium. I want to have it cut in slices. The peice is rather large, around 12 kg, 18×15×15 cm. Does anyone know where I can have it sliced (and polished) near the south of The Netherlands?
Does anyone have tips? Is there a chance that it falls apart while cutting?

[James Catmur]

You could ask a monument mason (grave stones, etc)

[SteveB]

Or look for a lapidary club. I had something hand cut rough by a paver with a diamond saw in a big angle grinder. you could do the same, slow and steady for the cost of the circular saw if willing and handy you likely won't find anyone experienced with that type of rock. I've seen people using water-cooled bench circular saws cut through agate geodes like butter, but it is expensive gear and needs steady experienced hands and often parts break off. Looking at your rock, I'd expect cracks and maybe breaks with the various hardnesses and densities so look for someone who can be careful and slow to go through. It's a niche set of skills and gear but a lapidarist is what you need and a local club should know who to talk to.

[Mathias]

Steve, James, thanks for your help. I attended a local mineral fair last Sunday in Schwalmtal, Germany, about 30 km from where I live. There was a vendor selling agate, and I took his business card and called him later. His saw was too small, but he knew someone who has a diamond saw with a 40 cm diameter. He gave me that person's phone number. I called and scheduled an appointment for sometime in July. It shouldn't be a problem for the saw—agate is quartz, with a Mohs hardness of around 7, while the minerals in Schalenblende reach only about 4.5. I'll let you know how it goes, even if the Schalenblende falls to pieces.

[Mathias]

Hi everyone,

I found someone nearby—about 60 km from home—who cuts agates using a diamond saw with cooling oil. Cutting the Schalenblende went well, and here are the results. I gave one good slice to the cutter as a thank-you.

Now, I’m looking for someone who can help with polishing. All the slices are 15–20 cm in size. They already look beautiful even without polishing.