How To Identify Synthetic Rough In Gemstone Parcels


Synthetic Amethyst and Citrine For Sale
Synthetic Amethyst and Citrine For Sale.

The vast majority of synthetic gemstone material is cut for the finished gem market. However, synthetic rough is also appearing more frequently for sale in gemstone parcels. Buyer beware: some synthetic rough is sold as natural material. In my estimation, 10% to 30% of some supposedly natural gem parcels may be synthetic.

Most experienced gem dealers can spot synthetic rough or at least suspect something is off. Unfortunately, the average consumer may find it almost impossible to identify synthetic stones mixed with natural rough in a parcel. Ultimately, whom you are dealing with is important in the gem trade. There are honest people and reputable dealers out there. There are some questionable individuals, too.

The vendor of these specimens told the photographer which were real and which were fakes. “Mix of Real and Fake Minerals,” Bangkok, Thailand, by Guy Courtois is licensed under CC By-SA 3.0
The vendor of these specimens told the photographer which were real and which were fakes. “Mix of Real and Fake Minerals,” Bangkok, Thailand, by Guy Courtois is licensed under CC By-SA 3.0

Tips For Spotting Synthetic Rough

  • A really cheap price for a gemstone parcel is a good indication it may contain synthetic rough. If the deal is too good to be true, so are the stones.
  • If the gemstones in a parcel look exactly alike in both color and size, they may be synthetic. For example, natural quartz stones usually vary in color and size and may show color zoning and twinning. (However, some manufacturing processes can create these effects, too).
  • A lack of crystal points can indicate synthetic stones. Most synthetic material is produced in large blocks. The makers break up or cobb them into smaller pieces to make the synthetic rough look real. However, these pieces will likely have no points because they would have to be cut. It’s unlikely (but not out of the question) that anyone would spend the time and effort on this for synthetic rough destined for a parcel.
  • Look for the pebble-like surface that may occur on synthetic rough, like the synthetic citrine pictured below. Once you know what it looks like it’s easy to spot.
  • Size is often a good indication of synthetic material. If the stone is very large and has great color, especially for the price, beware.
Synthetic citrine gemstone.
Synthetic citrine gemstone.

A Comment Regarding Makers Of Synthetic Rough Gems

I’ve always thought that those who synthesize gemstones (especially emerald, tanzanite, diamond, ruby, and quartz) should be required by law to put a dye tag in their products. Only visible when viewed under a certain wavelength of light, the dye would be a clear indication of synthetic rough. I’m aware of only one ruby manufacturer that does this. If all manufacturers of synthetic gems were required to dye tag their products, it would make no difference to the synthetic market. The fact is, most of these manufacturers choose not to make their product easily identifiable. Makes you wonder what their real market is, doesn’t it?

Among the gems for sale in a street market in Gujarat, India are rusty nails from boats, which are believed to bring good luck. “Goodluck for Sale” by Poonam Agarwal is licensed under CC By 2.0
Among the gems for sale at a street market in Gujarat, India are rusty nails from boats, which are believed to bring good luck. “Goodluck for Sale” by Poonam Agarwal is licensed under CC By 2.0
Gram Faceting Archive of Information
This edited version of an article by the late Jeff Graham is part of a special archived informational series from Gram Faceting. Used with permission.