Best direction to cut fossilized brown coral?

J

John Andrews

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Jan 24, 2003
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At a yardsale this morning I bought 3 large pieces of fossilized brown coral like stone (all they had) for the huge negotiated sum of $3 total! Now, this stuff I didn't even know existed, or anything like it. How would you cut the stuff to maximize the effect of the liniar-running "tubes"? My scanner shot craps a while back, so I don't have a way of sending a pic of this stuff. You set the stone down, and the "tubes" run in the upward direction, best way I can describe it. Great looking stuff, too.
 
John I think cutting perpendicular to the tubes would have a good effect, but cutting along their axis might look cool too. Are your pieces big enough to get scales from either direction? You might be able to do a small enough test to see which looks best without wasting too much cool material. What consistency is this stuff? Is it like stone? How porous is it - will it have to be filled? Great find, you lucky human!

Dave
 
Dave, the stuff is really heavy, and yes, the pieces are large enough to cut either way. I'm pretty sure it's coral. You can clearly tell it was a colony of living "tubes" packed together and shaped like coral. The tubes are about 1/4" or so, have a geometric shape, and grow together upright. Has some color as well as agate type makeup, not the typical calcium that you would expect.Maybe I'm wrong on what is is, rock shop here closed until Tues. It is really neat stuff, and I'll send info Tues. if I find out if is is indeed something else. Thanks for reply, Dave. Your name is on one of those chunks. Edit update- I checked with rock and mineral shop this AM, and it IS CORAL, called Iowa coral, a fossilized version of the stuff. I'll post a pic when I get the handle slabs cut and polished. The coral sells for $35 for a chunk smaller than a football, if you run across some, by the way.
 
Take it to your local tile guy, or mason. Only a stone cutting blade will do - with lots of liquid and patience.

I'm very interested in how this turns out. You may have seen my post on Alaskan Coral.

Fascinating as a handle material.

May I offer to buy any cutoff extras you end up with? (looking for pieces under 2" - for inlay/mosaic)
 
pendentive, Yes, I was emailed your excellent post on the coral, and yes, I would be glad to include you in some of the stone, thank you. I'm seeing the lapadarist tomorrow night to have it cut and polished. Exactly what size would you like it? I'm having some of it cut 1" X 1/2" X 5" for some handle slabs, and some short ones for inlays and solid handle sections. What ever you want, email me also, because I may see your mail before I get a chanch to check the forum.
 
Well, I had some slabs cut by a lapiradist. Cuts ran parellel with the direction the "tubes" run, or "with "the grain. Wow! The stuff is hard as agate, and beautiful. This fossilized coral has to be cut with diamond saw blades, but can be ground on a regular grinding wheel for the bevels. Diamond drill bits are required for drilling. My lapiradist is doing my drilling and polishing on the handle slabs, also. If you folks start using some of this material, remember the tooling required. Hopefully, you will have the luck I have, knowing a lap. guy close to home. They are pretty rare and really scattered out nowdays. The one here is the only one around for hundreds of miles. This rock runs in several colors, red, brown and green, orange combined with white swirls, and black coral, also. Next step, we are going to cut some crossways to see how it looks. I was showing some unpolished slabs today and got another knife order with coral slabs. I think I'm onto something here. Pendentive, your slabs should be done pretty soon, the guy is pretty fast.
 
Originally posted by John Andrews
Pendentive, your slabs should be done pretty soon, the guy is pretty fast.
Click to expand...
:D
 
is it re-crystallized, meaning there's calcium and silica filling all the pores and voids? if so, cutting parallel to the tubes will give a wood-like texture. however, if it's simply dried coral, the hollow tubes will give you a weird surface texture. better to patterns it against the tubes and get a mottled pattern.
 
Yep, it's solid and hard as agate, in fact. I could say it is recrystalized, and you can see small particles of what seems to be silica. You can see where voids were filled and then agatized or fossilized along with the coral. Even the original color was preserved. The whole surface of the sawed slabs sparkle with the small particles of what you describe as silica.Absolutely none of the material has any soft spots common with regular coral. There is no"texture" to the stuff when you cut it, just the very hard solid surface like any other agate. Of course, you see all that the coral was, in perfect detail. Thanks for the advice and reply, guy.
 
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