Selecting Rough for Designer Cabochons

by Bruce Frymire Sep 09, 2017 0 comments

My expertise comes from 20+ years of laboring many hours over various lapidary machines. I had to learn how to use these machines in order to finish 1000's of designer cabochons. 

My training started at the Mineral and Gem Society of Santa Rosa where I learned the basics on how to create a cabochon. My main goal was to create something that would be enjoyed by collectors and jewelry designers. Starting out was the toughest part, taking criticism was part of the learning, not everything I created was topnotch, a lot of people had good suggestions which I appreciated and it only made me better at this art.

Starting out:  The type of rough material you buy for designer cabochons really depends on the type of machines you have access to. Diamond lapidary saws, grinding, polishing, tumblers and buffers are the major machines needed to start and finish most lapidary jobs. My suggestion is to join a local Gem and Mineral Club that has a work shop containing all the machines and the expert help you will need to finish your first designer cabochon. The knowledge you gain as a member will be extremely valuable especially if you want to move your work base to your own shop.

 Many persons starting out at their local Gem club not only find the help they need but also new friends that can relate to your new interests. If joining a shop is not something you can do than reading books and watching many videos that are available on Youube would be a great help.

Selecting material to work with:   I like to keep my eye out for what's new (recent discoveries) and scarce or rare material that's generally sold at estate sales and sometimes at Gem shows.

Of course when I started out I picked out a lot of different type of material. To me, everything had the potential of turning out to be something special. I now have a yard full of wonderful looking rock. And some of it is just that, just rock and not really good for cabbing or jewelry. 

One thing I did learn from all this buying is when you buy a slab (a piece already sawed from the base rock), "Don't buy it until you dry it off". Most dealers will sell their slabs in water because the water brings out the colors, just as if it was polished. This water will also hide cracks and pits.

You will find this tip really important. When you look at a slab you will want to vision the cabochon coming from an area that doesn't contain a crack or pit so the slab has to be dry. If it's your intention to make wire wrapped jewelry, fine handmade jewelry or sell to designers, cabochons do not look their best with unsightly cracks across the face of the cab.  

Another tip to selecting your slabs or rough is to know the hardness of the stone or better yet ask to see a sample polished cab if available. Soft stones on the hardness scale will not normally produce a mirror polish. Even so, I've had a lot of soft material that does produce a mirror polish will a little extra work. Most times it produces a bright luster. One way to determine if it's hard or soft is, if the water runs off the slab it's most likely hard (dense). If the water is absorbed into the slab it is most likely soft and the polish won't be mirror like.  

Size of rough:  One tip on selecting your rough is make sure it will fit into the diamond saw you will be using. All saws have a limit to the maximum thickness of the rough. My yard also has a supply of large rocks that won't fit into my saws.  They are now a permanent fixture in my yard unless I purchase a bigger saw or find a Gem Shop that I will be able to use. 

Selecting a rough rock is not the same as selecting a slab. In a slab you can definitely seen what you are buying so you're not taking a chance at getting something you can't use. Sometimes the dealer will also have slabs available, ask him if they do. A Gem Show is also a good place to find someone that can cut your bigger rock for you, either for a price or a slice.

Fun places for slabs and rough:  

Rock and Gem magazines are a good source for listings.  Most Gem Shows will have a table full of used books and magazines.

Local Gem and Mineral club sales - annual shows in all U.S. states

Quartzsite, Arizona Jan and Feb annual flea market and gem shows

Tucson, Arizona, Jan - Feb annually - many shows thought the town.

  Denver, Colorado twice yearly spring and fall - many shows across town.

Good Luck on your new interest, you're going to experience a lot satisfaction.Bruce W. Frymire author and creator of this guideline on selecting material for Designer Cabochons.

On our website, https://designsbyshirl.com, I have cabochons and rough for sale. If your plan are to create your own cabochons we are now planning on retirement so our rough is now being sold.  I pre-form all my rough slabs, this will make it easier for you to finish into a cab for jewelry or specimen.  My site can also be a good resource to help you identify the material you may want to use for your projects, my plans are to create a catalog of cabs I have finished, I hope I can find the time to do this.

If you can't find what you need send us a note.