Making a Molehill out of a Mountain: How to Select the Best Gems Fast

During one of the Tucson shows, a fellow jeweler asked me where he can get the best purple sapphire melees. I disclosed the vendor I used (as a favor), but cautioned him with “you have to match them down.” “Ugh, then I’d rather buy them from you and pay more” was his response. That’s because he knows how much work it can be to match gems down from a parcel. If, on the other hand, you actually enjoy matching gems, and I very much do, then that gives me a ‘raison d’etre’ as a 'middle man' even among fellow jewelers.

Assuming that, as a client of mine, a fellow jeweler or vendor, you also like matching gems, let me explain how I do it here and you can see a video below: 

Matching gems is not for the uninitiated, and I have done this for about 15 years. To be precise, I was ‘initiated’ into matching gems in the fall of 2009, sorting and grading the entire inventory of a gem dealer in Manhattan – for fun.

Your eye gets trained over time to see color and clarity in a more nuanced way, just like a sommelier develops a taste for a good wine, or the way a photographer develops a feel for the right composition when she looks through the camera lens. You just have to keep doing it.

Another preliminary point I want to make is that sorting and matching gems from a parcel – we call it ‘selection’ in the trade – is not always permissible. You have to ask first of all if you need to buy the parcel, or if you can have a scoop (i.e. one carat or two), or if you can select. I try to avoid anything other than selection, unless I work with a vendor who has done the job for me and offers perfectly matched smaller sets. Buying matched sets costs more per carat but it can often be worth it because someone else has done the work for you. I buy all my demantoid garnets matched, and they are usually perfect.

Preliminaries out of the way, let’s get to work. Most parcels you see at trade shows will be presorted in some way. They might all be 2mm round green garnets, or 2mm green garnets sorted down into several shades (I’ve seen up to 6 shades). Sizes in a 2mm parcel would be 1.95-2.05mm. Others parcels can be surprisingly mixed – I’ve seen purple to blue sapphire come in bags with a 20 shades at least. Shapes, in small sizes, are almost always separate, but sizes not necessarily. Rarer sizes, like trillions, might be mixed in a parcel of 3-5mm trillions for instance.

You’ll then need to find out what your options are for selection, and if the price remains the same. Sometimes it goes up a little, sometimes it doubles. That might not be worth it. Try to find parcels that are fairly well presorted and from which you can select without markup.

Assuming you are favored by the gods and you have located such parcels at a good price, you might need to have a size sifted out, or you pick out a size by hand and measure it with a precise gauge, then match all other stones against it. Or, if you have a more or less correct size (i.e. 3x2mm oval) then you skip that step but still match what you are selecting down to be the same size as best you can, this will look nicer in your final product. Do the same with the color.

For color, I find it easiest to judge the gem upside down. Enough, if not most, gems land on their table when poured onto a sorting pad, so I start with just those and only flip gems over when that amount is picked through. (Remember, I don’t want to spend all day). Most gems are best seen upside down because then you can also check for the second most important characteristic of a nice gem: how flat it is. The flatter the gem, the more likely that it has window, and you don’t want window. So, be not afraid of deep gems, often they have great color. Ideally though you get the culets to all be well formed and the depth doesn’t vary too much between the stones. I pull out gems that are very deep unless I find the color irresistible.

In your final step, you need to flip each stone over and check them from the front to judge color facing up, as well as brilliance. In some gems, especially sapphire, the color seen from the front can be surprisingly different from what you expected. I have not found that to be the case for garnets or spinel or most other stones. Sapphires probably have the most color zoning, which would be responsible for these variations.

To match the colors, most people use sorting trays, though some of us just use our fingers since sorting trays don’t allow deeper stones to face up so you end up having to pick up the tray and tilt it around. 2mm gems stick better between your fingers (I don’t sort 1mm stones, and under 2mm I will not inspect every stone, but I’ll spot check however many I think I should given how the parcel looks). If at all possible, I move all or some of the gems out of the favorable light of the vendors booth and walk a couple of steps away or do a 360 turn to get out of the light. The larger the gem, the more time I spend on each one. I spend more time matching 3mm stones than 2mm stones for instance.

To give you an idea of how long the process takes, I spend 2-3 entire afternoons during the Tucson shows with the vendors where I have to sort, and I end up with about 15 parcels. And sometimes just 15 minutes at a booth where I know the gems will all look perfect anyway. I have to monitor my schedule carefully, and calculate what I might need before I see them again. For example: if I asked them to ship from overseas, I will get the mix I don’t want and I may not have the opportunity to return half a parcel that I don’t like. It’s not much liked because it’s a lot of work; therefore, it is more of a show attendee privilege. And it is one of the main reasons I attend the shows I do.

Let’s sum up your steps: check if selection is possible and at what price, have gems sifted if possible, select upside down but don’t forget to check your final selection from the front. Check your selection outside of vendor light.