The name “Herkimer diamond” is a misnomer. A misnomer is a name that is intentionally or inadvertently incorrect. It is incorrect because the crystals called “Herkimer diamonds” are quartz crystals rather than diamond crystals.

The name “Herkimer diamonds” has been used for over 100 years and is deeply ingrained in the language of local people as well as the rock and mineral community. The word “diamond” grabs attention and may imply a higher value to the person who hears it than the word “quartz.” As a result, some people might be misled or confused by the name “Herkimer diamond.” For that reason, anyone who is selling “Herkimer diamonds” must be sure to let all buyers know that they are purchasing quartz and not a real diamond.

Why is this important? In 2015, the Federal Trade Commission announced that the improper use of a mineral species or variety name could result in legal actions against the seller. Their proposed revisions to the Guides for the Jewelry, Precious Metals, and Pewter Industries held up “yellow emerald” (a variety of the mineral beryl known as heliodor) and “green amethyst” (amethyst that has been heated to convert it to a green color) as examples. The name “Herkimer diamond” will likely fall into the category of names that the FTC is working to discourage.

Although the name “Herkimer diamond” is a misnomer, and likely confuses a few people, the name also grabs attention and stimulates curiosity. If these crystals were named “Herkimer quartz”, they would probably not be nearly as popular, and far fewer people would know of and enjoy them. Without a doubt, they attract a lot of tourist money to Herkimer County every year.