Carat Measurement and Carob Seeds: Myth or Reality?
The sentence "Carob seeds are all the same weight; that's why jewelers used them as scales and carat measurement was born from here" is one of the most repeated carob information on the internet. Some of this sentence is true and some of it is legendary.
In this article, we discuss the origin of the word carat, the keration–siliqua–solidus relationship, how today's 200 milligram metric carat was standardized, and the findings of the scientific study that actually measured the weight of carob kernels. In the end, we try to answer the question "myth or reality?" with evidence.
Common Belief: "All Seeds Weigh the Same"
The relationship between carob and carat is often described in popular sources as follows: Carob kernels are surprisingly similar in size and weight; after drying, they do not absorb moisture and their weight does not change. For this reason, ancient merchants and jewelers used them as counterweights on scales.
This expression appears not only on social media, but also in columns and travel sites. For example, in a column published in Milliyet in 1997, it is stated that the carob seed is "a seed whose weight does not change" and that the Arabs, Seljuks and Ottomans used it as a measure of weight. On a site promoting the nature of Crete, it is stated that the seeds are "equal weight" and are in the range of 189-205 milligrams.
It should be noted that belief consists of two separate claims:
- Carob kernels have been used as a measure of weight in history, and this is where the word carat comes from.
- Carob kernels are extraordinarily equal in weight in nature.
The first claim is strongly supported by linguistic and historical sources. The second claim has been tested by scientific measurements and has not been verified.
Where Does the Word Carat Come From?
The relationship of the word carat with carob is indisputable. According to the Online Etymology Dictionary, the word is based on the Arabic word "carat" (qirat) from the Italian "carato" and the medieval Latin "carratus". This word in Arabic is taken from the Greek word "keration", which means "carob seed" and also a small unit of weight. Keration is the diminutive form of the word "keras" meaning "horn"; that is, the exact equivalent of the word is "small horn".
The "Kırat" article of the TDV Encyclopedia of Islam also states that the word is derived from a root meaning carob seed, and that it was translated into Arabic as "kîrât" and into Greek as "keration" through Aramaic, Hebrew and Syriac. Words such as "carat" in European languages and "quilate" in Spanish also come from this root.
The Online Etymology Dictionary notes that in English, the spelling "carat" is used for gold carat, and the spelling "carat" is used for gemstone weight, and this distinction is especially evident in American usage. In Turkish, the words "karat" and "ayar" are mostly used for the two concepts.
Keration, Siliqua and Solidus: The Chain of Measures of the Ancient World
The name of the carob seed became part of a system of measurement in the ancient world. According to the Online Etymology Dictionary, the Greek unit keration corresponds to the Roman unit "siliqua", and siliqua is the twenty-fourth of the solidus, the gold coin of Constantine the Great. In the Roman weight system, a siliqua is defined as 1/1728 of the Roman libra, or about 0.19 grams.
A word history article published in the Saturday Evening Post states that the solidus introduced by Constantine at the beginning of the 4th century weighed about 4.5 grams and was equal to 24 carats according to the carat standard of the period. Since solidus was considered pure gold, "24 carats" became the criterion for pure gold, while lower numbers began to indicate that other metals were mixed with gold. Behind concepts such as 24 carat, 22 carat, 18 carat that we use in jewelry today lies this historical logic of "one twenty-fourth".
The Islamic world also took over this system. According to the TDV Encyclopedia of Islam, the carat was used as one-twentieth of the miskal (dinar) in Iraq and one-twenty-fourth in Mecca, Egypt and Syria. In the system that Muslims took over from Byzantium, siliqua was used as the equivalent of approximately 0.19 grams; Although the carat values differed according to the sources in the Ottoman period, it was given around 0.20 grams. The encyclopedia also states that the carat is a solid of smaller grain units called "habbe" and that this ratio varies from region to region.
| Unit | Definition in sources |
|---|---|
| Keration (Greek) | Carob kernel; small unit of weight |
| Siliqua (Rome) | 1/1728 of Roman libra, about 0.19 g; 1/24 of solidus |
| Solidus (Constantine period) | About 4.5 g gold coins; 24 carats |
| Kırat (Islamic world) | 1/20 or 1/24 of miscal by region |
| Metric carat (today) | 200 mg (0.2 g) |
How Did the 200 Milligram Metric Carat Come About?
Throughout history, there was not a single carat. Each trade center had its own carat. In the carat article compiled by Wikipedia from historical sources, it is seen that pre-metric carats range from about 187 milligrams in Cyprus to about 216 milligrams in Livorno. In the same article, it is also stated that the Paris Chamber of Jewelers proposed an "international carat" of 205 milligrams in 1871.
The 200 milligram metric carat we use today was adopted at the beginning of the 20th century. Sources state that the Fourth General Conference on Weights and Measures, held in Paris in 1907, accepted the 200 milligram metric carat proposal. Countries legally adopted this unit on different dates; for example, according to the Wikipedia article, the USA switched to the metric carat in 1913 and the United Kingdom in 1914. The TDV Encyclopedia of Islam writes that the standard was determined by a commission in Paris in 1910. This difference in dates may be due to the fact that the adoption of the proposal and the transition to practice in countries were at different times.
The important point is this: 0.2 grams is a round value determined by an agreement. The sentence "A carob seed is exactly 0.2 grams" consists of reflecting this standard backwards to nature.
What Does Science Say? The Weight of Carob Kernels Measured
The study that most directly tests the subject is the article titled "Seed size variability: from carob to carats" published in the journal Biology Letters in 2006. Turnbull et al. weighed the seeds they collected from a group of carob trees and compared the results with other species.
The findings do not coincide with belief:
- The coefficient of variability in the weight of carob seeds was found to be 23 percent.
- The average coefficient of variability of the 63 species compiled from the literature is 25 percent; that is, carob kernels are not noticeably more "equal" than ordinary seeds.
- According to the value transferred from this study in the BioNumbers database, the core average of female trees is approximately 200.5 milligrams; a lower average has been reported for hermascent trees.
A coefficient of variability of 23 percent means that a significant portion of the kernels may be one-fifth lighter or heavier than the average. For a sensitive field like the gemstone trade, this is a sizable deviation.
So why were the seeds used as scales?
The most interesting part of the study is the explanation it provides for this contradiction. The researchers also conducted a perception experiment and found that people could visually distinguish between carob kernels about 5 percent in weight. They also noted that the variability of pre-metric carat standards was about 5 percent.
The conclusion reached by the authors is that the "myth" that carob seeds are of equal weight was created by human selection, not natural selection. In other words, traders may not have used random seeds, but may have created their own weighing sets by sorting out those that are similar in size and appearance. Seeds spread over a wide range in nature may have been reduced to a much narrower range thanks to this selection.
The University of Washington's Miller Library's note summarizing this study also emphasizes that kernels can be used as scales quite reliably, but dishonest sellers using non-standard kernels can exploit this situation. A popular fact-checking article similarly admits that locust bean kernels are used as a measure of weight and rejects the "constant weight" claim.
Connection with "Two Dirhams One Core"
The Turkish phrase "two dirhams and one core" is often connected to this story. The meaning and possible origin of the idiom What is Carob Seed? Since it is discussed in our article, we would like to make a small note here only in terms of measurement calculation.
In a 1997 column in Milliyet, it is written that "four seeds make one dirham" and that the dirham is about 3 grams. However, these two pieces of information do not match: if the dirham is about 3 grams and one seed weighs about 0.2 grams, one dirham corresponds to about 15 seeds, not four. In the verification article in Onedio, it is seen that different numbers circulate regarding the dirham-to-core ratio. This discrepancy suggests that the narratives surrounding the idiom are not based on a precise historical record, but on oral interpretations passed down from generation to generation.
Conclusion: Myth or Reality?
Putting the evidence together, the picture is as follows:
| Claim | Evaluation |
|---|---|
| The word carat comes from carob | Fact: supported by etymological sources |
| Nuclei were used as a unit of weight in history | Fact: keration and siliqua units indicate this |
| All beans weigh the same | Myth: variability is as high as in other species |
| Each bean is exactly 0.2 grams | Myth: 0.2 g is a standard adopted in 1907 |
| Traders may have weighed by choosing similar kernels | A scientifically plausible explanation |
The historical role of the carob seed is real; the exaggerated part is the "perfection" of the seed in nature. It is the human eye that selects the seed that provides the real sensitivity.
Frequently Asked Questions
How many grams is a carob seed?
The core weight is variable. Although the average values are around 0.2 grams, the individual cores can deviate noticeably from this value.
How many grams is 1 carat?
Today's metric carat is 200 milligrams, which is 0.2 grams.
Why is 24 carat gold expressed by "24"?
According to sources, this comes from the Roman tradition of dividing the gold coin solidus into 24 siliquas (kerations). 24 parts refer to pure gold, while lower numbers refer to the alloy.
Are carob seeds used as scales today?
Today, the main economic value of the kernel comes from food components such as carob gum obtained from its endosperm.
Carob Seed with Carob Türkiye
Carob kernel, which is the unit of measurement in history, is one of the important raw materials of the food industry today. As Carob Türkiye, we supply carob fruit, cracks, flour/powder, seeds and extracts.
For product information about the kernel Carob Seed You can review our page, for your wholesale and export requests Contact Now You can contact us on our page.
Domestic resources
Kallek, C., "Kırat", TDV Encyclopedia of Islam, V. 25, pp. 437–438. islamancyclopedia.
org. en/ Kirat Livaneli, Z., "Two dirhams and one core", Milliyet, 19 October 1997. nationality.
com. en/ Authors/ two- dirham- one- Core- 5373591 Syndulla, H., "We open the file: Is it true that the phrase 'two dirhams one seed' is based on carob seeds, which all come out with the same weight?", Onedio, November 27, 2020. onedio.
com/ news/ file- We are hurting- two- dirham- one- Core... Foreign sources
Turnbull, L. A., Santamaria, L., Martorell, T., Rallo, J., Hector, A., "Seed size variability: from carob to carats", Biology Letters, 2(3), 397–400, 2006. doi.
org/ 10. 1098/ rsbl. 2006. 0476 BioNumbers, "Average mass of seed (mythological weight of one Carat)", BNID 103348, Harvard Medical School. bionumbers.
HMS. Harvard. edu/ bionumber. aspx?id=103348 Online Etymology Dictionary, "carat". etymonline.
com/ it/ word/ carat Hollandbeck, A., "In a Word: A 24-Karat Word History", The Saturday Evening Post, December 15, 2022. saturdayeveningpost.
com/ 2022/ 12/ in- a- word- a- 24- carat- word... Wikipedia, "Carat (mass)". en.
wikipedia. org/ wiki/ Carat_(mass) Wikipedia, "Siliqua". en.
wikipedia. org/ wiki/ Siliqua Elisabeth C. Miller Library (University of Washington Botanic Gardens), "Ceratonia siliqua" newsletter article, May 2021. depts.
Washington. edu/ hortlib/ calendar/ news/ scholarMay2021... OpenIT, "Carob tree", Cretan Beaches. cretanbeaches.
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