What do I do with dark saturated rough?

This is a question that most faceters have... I have said this many times over the years, but it bears repeating.

"Do not buy rough that will not pass the white paper test in the first place. You are wasting your time if it will not pass the test."

What is the White Paper Test?

Sounds simple, right? You would be surprised at how many people buy dark rough. There are quite a few reasons, but I think the primary reason people buy dark rough is because of inexperience. They just do not realize it at the time, especially when they are new faceters.

Other reasons people buy dark rough

Dark rough is often inexpensive, a rough dealer generally knows what is too dark and will price accordingly. So people buy it because it is some times cheaper. Not always though, I have seen people at gem shows pay big money for rough I knew beyond a doubt would cut an over saturated dark finished stone.

Sometimes when you buy parcels of rough you have to take a few dark ones in the mix to get a good price on the parcel. This is how I generally get them.

Sometimes it's optimism (wishful thinking), people know it is dark, but it is inexpensive and "maybe it will cut lighter..." It will not in most cases.

Inexperience, like I said is the major reason.

What to do with dark rough?

To be honest I generally do not even bother if it does not pass the "White Paper Test". This type of rough is just not going to turn out well and not worth my valuable time to cut it (give it to someone for practice).

Think about it for a minute. How much cutting time a week do you get? Cutting time is generally small because of work, family, life in general, what ever. Do you want to spend these precious hours faceting a stone that in all likelihood will be too dark when you are done? No, is what I say.

OK, everybody has some dark rough. What to do with it?

Options:
#1 - Give it to someone for practice, tell them it is too dark, but hey it is free practice.

#2 - If it is too dark but has a little color (like a lot of Pyrope Garnets) and is good size it may be a good carving/cabbing piece of rough. A carver/cabber can cut it thin, and lighten it up. Sell it, although most carvers/cabbers will not pay much. Something is better than nothing. Dump it and move on to something worth while.

#3 - Cut the rough into small stones, this will help lighten it. Although I generally do not bother because I do not like to cut small stones.

#4 - If you can see a little color with the "White Paper Test". I do mean you can see some color, maybe not a lot but some (otherwise do not bother). Cut the stone in a smaller size, pick a shallow design like a checker board that has a simple single tier bottom (close to the CA of the material you are cutting). Or pick a rosette type design and just go for some color.

Here are three examples of designs that will work. There are lots of others look in my design Database.
Design Database Index Page

Chick - Addition #8
Pillow - Addition #8
Birdie - Addition #8

#5 - If you have the ability some dark rough works well in a "Fantasy Cut". In this type of cut, carving and faceting techniques are combined. For example a faceted crown and a hollowed out carved pavilion to lighten the rough could be used.

Note: I have heard some people say to cut the dark rough shallow below the critical angle. In my experience this does not do much. In some cases you might get a little color, but cutting below the critical angle makes a "dead" stone. The stone will not have any flash or sparkle.

Also even if you do get a little color by cutting below the critical angle the color is usually lost when the stone is set. Settings tend to close off the bottom of a stone, like in a ring. The only color you were seeing before the stone was set was transparent color, you were looking "through" the stone. When the stone is set you cannot look through it anymore and the stone is dark.

Last option is heating the stone. I do not recommend this option in most cases. There are many reasons I do not like to heat stones, here are a few.

#1 - You can bet that in most cases the rough/stone has been heated in the first place (by the miner, rough dealer, ect.), if there is any possibility of the rough improving. Especially valuable rough like Aquamarine, and Tourmaline. Always assume rough has been heated unless you know for sure it has not been heated.

Rough is almost always heated at the mine, by a rough dealer, or someone along the way. Think about it. If you were a miner/rough dealer and had rough you knew you could make worth more money by simple heating. Wouldn't you heat it? Remember a lot of rough goes through Bangkok, even if it is still sold as rough. What are the odds the rough has been heated? The answer is almost 100%, the rough has been heated. So in most cases if the rough will improve with heating it has been heated.

Never, ever buy rough assuming you can heat it and improve it. If you get some rough along the way you can heat and improve then great, but do not make the mistake of thinking you can make money doing it. If you think that, I have a bridge that I would like to sell you.

#2 - Heating a stone will change/lighten the color (hopefully). But you have no real control over what the stone will do. Often heating a stone will change/lighten the color into one that you do not want, even though it is not dark anymore. A lighter stone in a color you do not want (like colorless) is no better than a dark stone you do not want.

For example, People often buy dark over saturated red Zircons. If you heat a dark red Zircon it will usually lighten up, but it also will change color, going orange/brown to clear, depending on the stone and mine location.

The point is, if you wanted a red Zircon, it's not red anymore after heating. You paid for red, heating it made it useable, but a different color. In general you will pay a lot of money for a red Zircon (even dark), so you might as well have bought the less expensive lighter rough by the time you heat the red one orange/brown to make it usable and no longer red.

#3 - A stone will often fracture during heating. When ever heating you will fracture/crack some stones in the process. That is just how it goes. If you loose just one stone during heating (you will loose some) that you have spent the time to cut (cutting before heating helps).

Then you have lost your shirt. How many hours did you loose when the stone fractured during heating? 5 hours? 10 hours? What is your time worth? If you had paid a little more for a good piece of rough in the beginning how much further ahead would you be for the price difference? If there was a price difference.

#4 - Below is a list of stones that will sometimes heat. If the type of stone is not listed it will not heat, like Garnets. Remember that if you heat any stone it's always a gamble. You can never be sure what will happen. It all depends on the mine, the rough and what may or may not have been done to the rough already.

There is no way to give definite temperatures because depending on the mine, the rough will all react differently. Experimentation is the only way to find out what your rough will do when heated. Start low and add heat until the rough changes.

Quartz
Amethyst (Siberian, just a trade name now by the way, the original find in Siberia was very small and long gone) will usually heat lighter if you are careful and lucky. Not generally a good idea, heat will lighten and eventually turn it into Citrine depending on the mine location. Quartz often fractures when heated. 125 C to 400 C for most Qtz.

Citrine - Sometimes heat will eliminate the smokey color of some Citrine. Can make it go clear too. Quartz often fractures when heated.

Smokey - Will lighten to clear usually (sometimes a very pale yellow/green in between), but why bother? Quartz often fractures when heated.

Beryl
Aquamarine - Improves blue and gets rid of green tones. Do not bother in almost all cases Aquamarine is already heated before you get it. It will often crack and is fragile during heating. By the way there is a significant market for natural color Aquamarine.

Here is an article on heating Aquamarine. What is the True Color of Aquamarine? How is it Heated?

Topaz - Some will lighten with heat and heating is actually part of the process when "nuking" it from clear to blue (nuke then, heat from brown to blue). In general you will not have any reason to heat Topaz. Some types of Topaz are very fragile and heat will destroy them, like Imperial or some Afghanistan material. Also there are some types of Topaz, depending on locality that are not color stable (New Mexico, some Afghanistan). 125 C to 400 C for most Topaz

Tourmaline - Some Tourmaline will lighten slightly or even a shade or two depending on the mine and type. In almost all cases Tourmaline has already been heated, if it will heat, before you get it. Generally Tourmaline is not cheap and not worth the gamble of heating. Buy good rough in the first place. 100 C to 700 C for Tourmaline. Some locations of Tourmaline are very heat sensitive and are very easily damaged by heat of any kind. Expect to loose a fair amount of stones to damage.

Zircon - Red Zircons will usually heat lighter and change color, they are pretty stable and usually do not crack too much, but there will be some heat damages once and a while. 400 C to 1000 C for Zircon

I know there are quite a few people that think that they can get a deal on rough and then magically heat it to get quality material. I have them ask me all the time how to do it.

I have one thing to say about that. Those types of people keep Las Vegas in business. There is a sucker born every minute.

There are occasions where heating is a viable option for a piece of rough/cut stone, but you will be much better off to buy good rough in the first place.

My advise is... Spend a little more and buy quality rough in the first place, time is money. Your time is valuable, hobby, pro, or just having fun, you only get so much time, no more. Spend your time wisely, cut something worth while to start with.

If you get some rough you just want to heat/play with or that came in a parcel that you just want to get something out of (and you have the time). Then go ahead and try heating, have fun. You may or may not be happy with the results.

But in most cases you will find your time better spent cutting something worth while. In the first place.

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