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[MNDesigns]

I started cabbing this pretty larimar and almost as soon as I started it started flaking and chipping at the bottom. I should have stopped right then, but I didn't and lost quite a bit of material. It also developed a crack that goes all the way through at the top. I'm used to cutting agate so I'm not sure what to do with difficult stones like this.

I have more of the same slab so I plan to start over. I have some black rock I can slice thin to back it and I guess it also needs to be stabilized. I have 3 questions about the process.

1. In what order do I do this? Back the whole slab, stabilize the whole back slab, and then trim and cab?
2. What adhesive do u recommend for backing?
3. How do I stabilize the larimar?

Thank you so much!




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[Orrum]

Larimar crumbles on me too but usually at the polish stage. I soak mine in water before starting to cab for a few hours. Then you need to grind extremely lightly with lots of water. TAKE bresks, let it cool when polishing. Best to handle Larimar like you would a high strung horse or fractious woman....Very slow and easy deliberately feeling everything gently and with a touch as soft as a angels wing brushing your face! This grasshopper shall bring you the reward you seek. THAT being said lapidary is sometimes a art form that endures despite breakage! LOL. That's one reason Larimar is so exspensive!

[Jhon P]

Bill is correct, light pressure and take your time.  Don't grind with 60 or 80 grit. I alway start with 220 and pleanty water.  The vibration from the 80 grit seams to cause the stone to fracture. The rough is too expensive to have it fall apart on you

[Amethyst Rose]

I have found that larimar reacts to metal wheels the same way a lot of jade does.  When I have any larimar to cut, I use only Novas for shaping and only with lots and lots of water.  This will reduce the flaking,

Good luck in the future

Bob Johannes
The Amethyst Rose

[MNDesigns]

I was on a 100 hard wheel. I'll try starting on the 220 soft on my next try.

You don't think its necessary to stabilize or back it?

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[MNDesigns]

This is the material I have left to work with.

[Jhon P]

Re shape the first one. It will be good practice.  You can do it!!  Don't get in a rush.

[finegemdesigns]

My advice for cabbing Larimar?

Don't cab Larimar.

 

Seriously it's not worth the trouble IMO. But if you insist, rough out your cabs with no coarser than 260 diamond on metal. Also don't make cabs with sharp or pointy edges. Rounded shapes are safer.

[MNDesigns]

My advice for cabbing Larimar?

Don't cab Larimar.

 

Seriously it's not worth the trouble IMO. But if you insist, rough out your cabs with no coarser than 260 diamond on metal. Also don't make cabs with sharp or pointy edges. Rounded shapes are safer.

I wish I had just bought a cab, but it's a client request and I needed a specific shape...and the prices of ready made cabs made me run out to buy a chunk of rough.

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[Ranger_Dave]

I have a few pieces of larimar that I've been holding on to until I learned more. Let me recap and see if I got it right:

Go slow.
Lots of water, keep the stone cool.
Go slow.
No metal wheels, keep vibrations down.
Go slow, don't use much pressure, light touch.

My cab machine has a speed control. I was thinking to run it at about half speed.

I might have time next week to do some cabbing as soon as I finish restoring a 12 inch rock saw. I'll post some pictures of both, the rock and the saw, later.

[Greg Hiller]

As you have mentioned it's a good idea to back the entire slab with some low cost stone.  I will use most any stone that is strong, yet easy to cut away.  I use 330 epoxy for the backing of the slab.  I also strongly agree with the comment, don't try and make shapes that have any sharp or protruding edges.  If you don't have a coarse Nova wheel, you can always put on a new 220 silicon carbide sanding belt and just use lots of water and take your time.  When the cab is complete and polished if you want you can grind away some of the backing stone before setting the stone.  It's too bad this material is so darned expensive, it's a challenge to work with, but polishes so beautifully, and people really like it. 

[finegemdesigns]

As you have mentioned it's a good idea to back the entire slab with some low cost stone.  I will use most any stone that is strong, yet easy to cut away.  I use 330 epoxy for the backing of the slab.  I also strongly agree with the comment, don't try and make shapes that have any sharp or protruding edges.  If you don't have a coarse Nova wheel, you can always put on a new 220 silicon carbide sanding belt and just use lots of water and take your time.  When the cab is complete and polished if you want you can grind away some of the backing stone before setting the stone.  It's too bad this material is so darned expensive, it's a challenge to work with, but polishes so beautifully, and people really like it.

It's overrated IMO and the reason it sells well is because it has been hawked on the TV jewelry channels. I sell blue jadeite cabs that are harder, take a better polish are arguably rarer and more beautiful. But it's difficult to get even a modest $3.00 per carat wholesale for well cut cabochons.

Why is that?

[tetonartgallery]

Buy finished cabs, it is a lot less frustrating.

[Ranger_Dave]

Buy finished cabs, it is a lot less frustrating.

But not as fun.

[Jhon P]

Don't let them scare you. It's not that bad. I use a 8" diamond 220 hard wheel. Easy on the pressure, the speed of the wheel dose not seam to matter. I than go thu the diamond belts up to 6 mil. And polish with Linda A on leather. I think that thicker slabs hold up better. I have never had a problem. Here are some that I have done