Carob Seeds and Diamonds - Myth or Fact

Updated: May 15


There was a time, when in order to weigh anything you needed a standard unit of known weight in your possession. Believe it or not, carob seeds used to fill this role. The modern unit of weight for gemstones, the word carat, owes its derivation to the same pathway that named the carob, which was originally used by jewellers to weigh their precious metals and stones. You can see the resemblance in its Greek name keration and its Latin name Ceratonia.


In order to understand if the carob seed is a myth or fact a sample of 50 carob seeds was analyzed using the Vibe QM3 Grain Analyzer.

The weight of 50 seeds sample was 9.6 grams, 4% lower than expected, if each seed had a uniform weight of 0.2 grams. In fact, with further detailed analysis it was found that there was a large variation in the weight of each seed – ranging from a maximum of 0.25 grams to 0.15 grams. There was also a corresponding large variation in the dimensions of each seed.

The results above are based on accurate image processing of the seed sample and show the statistics and distribution of the length, width, area and length to width ratio. The results clearly show that not all carob seeds are equal.

Most people reaction when presented with this data was that the carob story was a myth as carob seeds vary so much they could never be an acceptable weight measurement standard.

However, the real question is, what was the alternative? Can we judge the history with today’s mindset and technology ? Was a 5-10% variation good enough hundred years ago?

In reality, although it seems that carob seeds were used as a standard of weight, they were probably also used as a good way to fleece people, as it would be pretty simple to keep a heavier set and a lighter set on hand in order to use the one that suited your needs at the time.

The same story could be told with any grain or seed today without an accurate and reproducible method of cross checking.

The Grain Guru

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