Designs and Designing: GemCad

Just Ask Jeff :There seems to be a lot of questions out there about gemstone designs and designing.Here are some common questions and answers about GemCad.

7 Minute Read

There seems to be a lot of questions out there about gemstone designs and designing. Here are some common questions and answers about GemCad Files.

Have ".gem" (Gemcad files) ever been released?

By me? Well contrary to what a few people think ".gem" files were released online by both me and Bob Keller of "Bob"s Rock Shop" in the early days of both of our websites (1995 or so, maybe a little earlier for Bob). Perhaps by other people also that I am not aware of.

Releasing ".gem" files is not a new concept and frankly the "leaders" were doing it almost a decade ago.

The fact of the matter is that if ".gem" files were practical to distribute, most everyone would be using them. They are not. Which is why I (and other people) have gone to the trouble to post designs I want to give away online as just regular web pages (.html or .pdf) that anybody, any where online can use.

Why don't I release .gem (Gemcad files) anymore? The answer to this question is a business, practical, and personal one.


When we released ".gem" files originally many years ago we quickly learned that there were (and still is) a lot of tinker's out there. By this I mean that within a very short time of releasing the ".gem" files there were many bastardized versions of our original designs being passed around in ".gem" format. Both Bob and I quickly had people writing us to complain that our designs were wrong or did not work. In every case the designs that were wrong were not originals and had been "tinkered" with by somebody (usually by some one clueless). This needless to say created a lot of problems and was just too much to put up with. Bob Keller and I both decided no more ".gem" files.


Anybody familiar with the "Napster" music scandal and the continuing problem the digital age is causing all types of entertainment industries? Right… From a business stand point releasing a digital file of anything is basically making that product or information uncontrollable.

I hear people say, "I would pay for them anyway…" Yes, some people would, probably most people in the USA would, but a lot of people would not. As usual it is not the honest people here that are the problem.

But when things begin to get into gray areas and just too easy to abuse, the problems begin. Here is an example of what I mean.

I have a question for people. If you do have a copy. Did you pay for your copy of DataVue? No? Why not?

DataVue never had publishing rights to many of the designs in it and the authors of those designs in a lot of cases never gave permission for their designs to be published in DataVue. Essentially, by down loading and using them you are stealing.

Most people are perfectly aware of the fact that DataVue is not licensed to publish at least some of these designs. The authors of DataVue do have the rights to some of the designs, but certainly not all. The facet of the matter is that people know this and still down load and use (try to anyway) these designs all the time.

This is of course a gray area (I do not think it's all that gray but none of my designs are in it) which is what I am talking about. DataVue was/is advertised as "FREE" and down loadable by people online. The people providing the DataVue files do not have copyright permission of many of the designers. But DataVue is still being given away and used by many people, maybe you.

Now as we all know most people that have been faceting for any length of time have a copy of DataVue laying around some where. They did not have to pay for it… it was free right?

Do you think this same type of thing will not happen to any ".gem" file(s) released digitally? Especially a file from a well known designer, or a really special design or set of designs?

If you are in doubt just search the USFG mail list files and see how many times the subject of where do I get and how do I install DataVue has come up on the list. The answer is all the time…

People also say, "Well they can just copy it on a copy machine…" Yes, absolutely true. However, copying some thing on a copy machine like a book takes some effort and cost, plus the person doing the copying knows beyond a doubt they are breaking the law, it is not a gray area. That is quite a different thing than a digital file, which is just a click of a mouse away from anywhere in the world and will travel like wildfire.

Lets also keep in mind that the vast majority of software and digital files for anything are pirated copies in most foreign countries. There is no way to enforce anything outside the USA, and generally it would not be worth the effort if you tried.

People say, "Well they can enter the design in Gemcad themselves…" Yes, again quite true. But most people that have learned the ability to use Gemcad to that level are honest and not really interested in stealing or causing trouble. It is the opportunist's and bottom feeders that are looking for a free ride and something to steal, giving these bottom feeders digital files would be just what they are looking for.

In my opinion people are welcome to put designs in Gemcad and figure out how they work for their own private use. Frankly there is no way to stop people from doing it and as long as the files are for their own private use only, not really a problem.

Painters often learn how to paint by studying the masters, designing is no different. The important issue is that people not copy and distribute other peoples work or make small changes and claim it as theirs. It is OK to learn using other peoples work, just be aware that anything you claim as yours needs to be different enough from another work of some one else's to stand on it's own and satisfy the copyright laws.


Many people tell me they just want the Gemcad files so they can make changes, and or angle changes. Frankly my designs are optimized for particular goals and in general should be cut the way they are published.

I will freely admit that one of my pet peeves and I know other designers like Fred Van Sant thought so too… Is people "tinkering" and supposedly "improving" my designs, especially if they then pass the tinkered version around with out clearly marking it as being "tinkered with".

If you want to make facet and L/W changes to a design, then you have fundamantally changed the original design. My advice is to work on and create your own designs. Learn to use Gemcad. My point here is that once there have been some facet changes the design is no longer the design anymore and you might as well do your own.

Just making some angle changes to cut a design in a different material is a simple thing to do and does not require a gemcad file to do so. I also would not consider that tinkering.

In most cases I have listed a refractive index range for each of my designs and you do not have to change a thing. If I have not listed that design for a particular refractive index, it almost always means that, that design is not suited for that refractive index without major changes.

In Layman's terms - Many designs will not cut well or can even be made to work (performance wise) outside of the refractive index(es) the design was made for, without dramatic changes and redesigning.

Like I said before, if you make major changes to a design then it is no longer the same design. So what is the point of making changes?

In other words I create designs and optimize my designs for as wide a range of refractive indexes as the design(s) will perform well in and still maintain the integrity/idea/performance of the original design concept. In general I have pushed the design envelope and performance as far as that design will go, there is no more.

Releasing ".gem" (Gemcad) files - As you can see releasing ".gem" files is not some thing that I will do for all of the reasons above and a few more I have not gone into. If some one else wants to release ".gem" files of their work, then they are certainly welcome to. Just do it. You are not by any means breaking new ground, it has been done.

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Jeff R. Graham

The late Jeff Graham was a prolific faceter, creator of many original faceting designs, and the author of several highly-regarded instructional faceting books such as Gram Faceting Designs.

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