Carat (mass)

Etymology and History

• The word 'carat' comes from the Italian 'carato', which was derived from the Arabic 'qīrāṭ', borrowed from the Greek 'kerátion'. 'Kerátion' means carob seed, which is a diminutive of 'keras' meaning horn.
• Carob seeds were originally used to measure jewelry, but they were not actually consistent in mass distribution.
• Different countries had their own carat measurements in the past.
• In the 1570s, carat began to be used for measuring diamond weights.
• Today, the carat is used for measuring gemstones and pearls.

Standardization and Historical Definitions

• In 1871, an international carat of 205 milligrams was proposed.
• In 1907, a metric carat of 200 milligrams was proposed and accepted.
• The metric carat became compulsory by law in France and was later adopted by the United States and the United Kingdom.
• Different locations had slightly different mass values for the carat in the past.
• The international carat of 205 milligrams became widely adopted, but some locations had specific carat values.

UK Board of Trade

• The original Board of Trade carat was approximately 205 milligrams.
• In 1888, the Board of Trade carat was changed to approximately 205 milligrams.
• Some metric countries used the Board of Trade carat, even though it was a non-metric unit.
• The Board of Trade carat was divisible into four diamond grains.
• The Board of Trade carat was primarily used for measuring gold and had limited application.

Carat as a Unit of Mass

• Carat is a unit of mass used for measuring gemstones and pearls.
• It is equivalent to 200 milligrams or 0.2 grams.
• The term 'carat' originated from the carob tree seeds which were used as counterweights on balance scales.
• The carat weight affects the value and price of gemstones, with larger carat weights being more valuable.
• The carat weight is often used in conjunction with other factors like cut, color, and clarity to determine the quality of a gemstone.

Carat vs. Karat and Conversion

• Carat, as a unit of mass, should not be confused with 'karat', which is used to measure the purity of gold.
• Karat is a measure of the proportion of gold in an alloy, with 24 karat being pure gold.
• Carat and karat have different origins and meanings.
• Carat can be converted to other units of weight, such as grams or ounces.
• 1 carat is equal to 0.2 grams or 200 milligrams.
• In the Imperial system, 1 carat is approximately equal to 0.007055 ounces.

Carat (mass) Data Sources