How to select quality natural Turquoise rough part #1

This is a very big subject and it will probably take many articles to explain the various ins and outs of buying and cutting natural Turquoise rough. But this is a start...

These are my personal experiences and opinions. Some people may not agree, some may, but this is what I look for and how I select and work with this type of rough. If you read these articles and pay attention, what works for me will work for you.

I cannot stress this enough and I know some people will not listen to me, but especially as a beginner buy Turquoise (or any rough for that matter) from a quality suppler, preferably an expert. Stay away from eBay in my opinion it is full of scammers, crooks, and people that just do not know what they are doing.

Buying from an expert will save you a lot of money as well as frustration. A quality supplier will have already done the grading and sorting on their rough.

Yes, you will have to pay for it, but you will get what you pay for.. which is almost never the case when buying from eBay in my opinion or some unknown supplier. Believe me there are a lot of people selling Turquoise that are absolutely clueless about it. Many of these people know nothing about Turquoise, cabbing/cutting Turquoise and nothing about lapidary. They are just trying to hustle a dollar, so be aware of them and stay away from them.

A quality suppler that has real life experience and knows what they are doing will save you money and time in the long run as well as make the cutting much more enjoyable.

That being said... As in anything in life there are many different colors and types of Turquoise as well as many people who like the various colors and formations in Turquoise. Some of what makes a particular Turquoise better than another type, is just personal taste for color, shape, matrix and just about anything else that you can think of. People are all different and they like different things.

That being said there are some basics that any quality Turquoise cab/rough should have. What are the basics?

Any Turquoise you want to cut should be solid, stable, and hard enough to take a good polish and wear well.

Note: Turquoise is not considered a hard stone, generally 3 to maybe 4.5 on the Moh's hardness scale. That is one reason that Turquoise is often backed before being cut. This is another subject and will be discussed in a later article. But for right now suffice it to say the backing is usually a type of epoxy/resin that is applied in a thin layer to the back of the rough before cabbing to add stability and support to the stone.

Turquoise that you are planning to cut should be thick enough and directional enough to cut a nice cab out of... and usually preferably backed before cutting. By directional I mean the Turquoise should be large enough and level enough to cut. Turquoise often forms in very convoluted layers and shapes, many of which can be cut, but many that will not yield a desirable stone. So it is important to select pieces of Turquoise rough that will yield quality stones.

It is also important to select Turquoise that is solid and will cut well. A lot of Turquoise can be porous, pitted, chalk, fractured, and just plain bad. As I said it really takes and expert to know what good quality Turquoise looks like. Even as an expert there is always some thing new and occasionally you can be fooled.

Below I am going to list pictures of rough Kingman Turquoise, next to the pictures I am going to list the pros and cons of the piece. Look and read through the pictures and descriptions. It will get you started on the road of learning about the fun and fascinating world of Turquoise.

Left: This is a mixed piece of natural Turquoise. This piece is basically what I would call a "good cutter".

What and why? OK take a look and see that the piece of Turquoise is fairly large. So the veins and layers in the stone are easy enough to work around.

Notice the figure "8" in the middle of the stone that has 2 pockets of matrix, or basically waste rock? The knob of solid Turquoise in the left of the picture will be sliced off and will cab easily.

The layers that curve around the pockets are solid, and when you examine the back of the stone (below) you can see that the layers are solid and run through the entire piece of rough.

Left: This is the bottom/other side of the same piece of rough above.

So now that we know the layers of Turquoise are both solid and all the way through the piece. It is easy enough to saw/slice the back layer off and cut it.

The piece on top of the brown pocket of matrix (rock) will be sliced off and cut into smaller pieces that will lay flat and should be backed and then cut.

The larger layers are pretty flat and will cut and polish quite easily. I would back them.

This piece of rough will yield pretty well, there will be some loss around the matrix pockets. But notice that the Turquoise is not only solid, and the layer is a good thickness all the way through the stone, this piece is also solid good color.

Left: This is a mixed piece of natural Turquoise.

Note the two (2) layers of Turquoise separated by clay and sand. Also notice it is clay and and, not rock matrix. Clay and sand will not polish, rock matrix will usually.

This particular piece of material is problematic and will really depend on the cutter and the use that the cutter wants to get out of this material.

The two layers would be very easy to split apart and basically end up with two separate layers of Turquoise.

The two layers are on the thinner side and will require backing in order to make the pieces useable. Of they could be used for inlay work, which requires thinner solid rough.

Left: This is the back side of the piece above.

As you can see this piece of Turquoise is solid and the 2 layers are solid and go through the piece of material.

Like I said this piece is problematic, it depends on what the cutter needs. These two layers will split apart and with backing cut very nice Turquoise cabs.

These layers would also work very well for inlay work (note the layers are flat and straight) as the thickness of the layers is almost ideal for inlay work.

As I said this is a piece that a cutter may or may not want to buy depending on the use. As a general rule on any good color solid Turquoise that will yield well.... I would buy them.

Left: A piece of Kingman Turquoise

As you can see this piece of Turquoise is solid... depending on the sections. But the layers are curved and the yield on this piece would be lower.

The back of the stone where my thumb is... is solid Turquoise. The front part of the stone has layers that are convoluted.

The rough would yield "OK" but not well. I would probably pass on this piece of rough.

Again there is some usable rough in this piece, but the yield would be low. If the price of the rough was reasonable enough I would probably buy it. Expensive, no I would pass.

Left: This is the back side of the piece above.

As you can see this part of the piece of Turquoise is solid and the 2 layers are solid and go through the piece of material where my fore finger is.

So the waste is underneath my fore finger and the wide layer of material above my thumb. The waste on this piece I would guess might be about 60% to 70%, so depending on the price of the rough this might be a stone to pass on.

The knob on the right side will cut of to be a separate piece. The 2 curved layers would have to cut off and be worked out.

The thicker layer would be a separate piece and cab a good stone.

Left: This is a large layer of Turquoise.

Look closely at this layer of Turquoise. Most people would think this is a good piece of Turquoise and that it will cut well.

The piece is thick, large and if buying it would be fairly costly because the piece is large.

This piece weighs about 1/4 of a pound and if the material was say... $600/lb. The piece would be about $150. The color is good, it looks about the same as the piece above.

Do you think this is a good investment?

You would be wrong if you think so.

Left: This is the same large piece as above.

As you can see I snapped this large layer of Turquoise in half very easily with just my hands.

Why and How?

How... Well a good test of any layer of Turquoise is to apply a bit (not extreme) of pressure and see if it crumbles or breaks easily.

If the material breaks easily with not a lot of hand pressure...

Then it is a very good bet that the piece of Turquoise you are testing has some internal problems and that you probably do not want to buy it.

Left: This is the same large piece as above.

Why?

Ok look very closely at the picture to the left and the same piece of material in close up pictured below...

See the gray/white pockets of rock/clay mixed in the very nice blue of this piece of material?

At first glance most people would assume that the gray/white is either on the out side of the rough and or that the material is quartz.

That is wrong. This material is basically soft clay and it runs in pockets through out the layer.

Left: This is the same large piece as above, close up.

As you can see the entire material is shot through the entire layer of this piece and that it is not only soft, but it is basically chalk.

The gray/white in this Turquoise will not hold together during the cutting process and even if it did it will not take a polish and will pit.

So while this piece of Turquoise at first glance looks quite good and has nice color.

Because of the gray/white clay this is definitely not a piece of Turquoise that you would want to buy.

This is not unusual in Turquoise depending on the mine and the material. turquoise can really require a lot of experience and an expert to select and cut it well.

Just Ask Jeff Index

E-mail to inquire or order: jeff @ faceters.com or jeff @ cabbers.com