CARAT

What is a Carat?

A carat is a term used in fine jewelry to express two completely different measurements: purity (for gold) and weight (for gemstones like diamonds).

The word originates from the ancient Greek kerátion (carob seed), as uniform carob seeds were historically used on balance scales to weigh precious items.

A gold carat measures the purity of gold on a 24-point scale. Because pure gold is naturally very soft and prone to bending or scratching, it is often melted down and mixed with alloy metals (like copper, silver, or zinc) for strength and durability.

24 Carat (24K): 24/24 parts gold = 99.9% pure gold
22 Carat (22K): 22/24 parts gold = 91.6% pure gold
18 Carat (18K): 18/24 parts gold = 75.0% pure gold
14 Carat (14K): 14/24 parts gold = 58.5% pure gold
9 Carat (9K): 9/24 parts gold = 37.5% pure gold (Common in UK/Australian jewelry).

A diamond carat is a unit of weight used to measure diamonds and other gemstones.

The standard unit: 1 carat = 200 milligrams (0.2 grams).
One carat is divided into 100 points. For example, a 0.50-carat diamond is often referred to as a "50-pointer" or half-carat stone.
Carat measures mass, not physical dimensions. Two 1.00-carat diamonds can look different in face-up size depending on how they are cut (e.g., a deep cut makes a diamond look smaller top-down, while an oval or shallow cut can make it appear larger).

THE INDIAN "CARAT"

The Indian equivalent of the carob seed (kerátion) is the Gunja seed (botanical name: Abrus precatorius), commonly known as the Ratti seed (or Raktika).

Just as Mediterranean traders used carob seeds to establish the carat, ancient and medieval Indian goldsmiths and jewelers used the Gunja seed as the baseline unit of mass, called the Ratti.

Like the carob seed, Gunja seeds were favored because they maintain a remarkably uniform weight of approximately 1.75 to 1.8 grains (~0.105 to 0.1215 grams, or roughly 0.6 carats).

The traditional Indian gold units—such as the Masha (8 Rattis) and the Tola (96 Rattis or 12 Mashas)—were directly based on multiples of the Ratti seed. Even today in North India, astrological gemstones are frequently measured and bought in Ratti rather than carats.

IN BENGAL

In Bengali culture and traditional jewelry trade across West Bengal and Bangladesh, রতি (Ratii) and ভরি (Bhari/Bhori) are units of mass used in a unified traditional measurement system for gold and silver.

The fundamental hierarchy of traditional Bengali weight units is:

Rathi ---> Ana ---> Bhori (or Tola)

16 Anas = 1 Bhori (Tola)
6 Rathis = 1 Ana
96 Rathis = 1 Bhori (16 X 6)

When buying traditional jewelry (like a bangle or chain), Bengali jewellers express the metal's weight in Bhori, Ana, and Rathi. The terms Bhori (used predominantly in Bengal) and Tola (used in northern and western India) are functionally identical in weight (11.664g).

NOTE

Beyond establishing historical weight systems, both the Mediterranean Carob seed (kerátion / Ceratonia siliqua) and the Indian Gunja seed (Abrus precatorius / Ratti) have served significant cultural, medicinal, and practical roles across human history.

Carob Seed (Kerátion)

The pod surrounding the carob seeds is rich in natural sugars. In biblical tradition, carob pods were referred to as "St. John's Bread" because John the Baptist was said to have survived on them in the wilderness. It was also widely used as animal fodder across the Mediterranean.

Carob pod pulp was dried, roasted, and ground into a naturally sweet, caffeine-free powder used as a hot drink or sweetener—a practice still widespread today as a cocoa alternative.

Carob pulp was used in traditional Greek, Arab, and Mediterranean medicine as a digestive aid to treat diarrhea, soothe sore throats, and suppress coughs due to its high tannin and pectin content.

Today, the endosperm of carob seeds is industrially extracted to make Locust Bean Gum (E410), a major thickening agent, stabilizer, and emulsifier used in ice cream, cream cheese, sauces, and infant formula.

Indian Gunja Seed (Ratti)

Gunja Seed (Ratti) is highly toxic in its raw state (containing abrin, a potent ribosome-inactivating protein similar to ricin), the Gunja plant occupies a unique place in Indian tradition

In traditional Ayurveda, Gunja seeds are classified under Upavisha (semi-poisonous substances). After undergoing a meticulous detoxification process called Shodhana (boiling the seeds in milk or kanji for hours), purified Gunja is used in classical Ayurvedic formulations:

Hair Growth & Scalp Formulations
Joint & Nerve Pain

Due to their striking appearance—glossy scarlet red with a jet-black cap—unaltered Gunja seeds were drilled and strung into traditional necklaces, rosaries, and tribal ornaments throughout rural India (hence its common name, Rosary Pea).

Bengali Gaudiya Vaishnavism: The red and black seeds (Gunja mala) are associated with Lord Krishna and Radharani, frequently worn as garlands by devotees.

Tantra & Folk Protection: In Indian folklore, wearing or keeping Gunja seeds is believed to ward off the "evil eye" (Nazar), bring good fortune, and protect against negative energies.

In ancient and medieval times, crushed raw Gunja seeds were reportedly mixed into paste to tip arrows or small darts (Sui) used in covert poisonings or hunting.

It is occasionally used as a first name and also an affectionate home nickname for girls—often short for names like Ratna (gem), Rati (delight/beauty), or Rattika.

In Northern India (particularly among Punjabi and Himachali communities), "Ratti" exists as a legitimate surname or clan name (e.g., within certain Kshatriya or artisan lineages).

People frequently confuse the weight unit Ratti (रत्ती / রতি) with the classical Sanskrit name Rati (रति).

Rati (spelled with a single 't') is a well-known Hindu female name. She is the Hindu goddess of love, desire, and carnal pleasure, and the consort of Kamadeva.

In Bengali households, Rati (রতি) or Ratna (রত্না) may be used informally, but parents rarely give "Ratti" as an official name on certificates because of its direct association with tiny gold measurements ("রতি-আনা-ভরি").