Meaning
The term carat is mainly used in goldsmithing and metallurgy with a dual meaning, that of a unit of measurement of the mass of precious materials or that of an indicator of the purity of gold alloys.
As a unit of weight, the carat is used for diamonds and other precious gems and equals 0.2 grams. The weight of a diamond is measured in cents. The approximation of the weight of the diamond to the higher number is allowed only if the thousandths correspond to the number 9 (instead of 5 as is usually done). Therefore, a ring with a diamond weighing 0.999 carats is a 1.00-carat diamond, while a 0.998-carat diamond is a 0.99-carat diamond.
As a reference for the purity of gold, it must be considered that generally raw gold is alloyed with a metal, for example copper, silver, palladium, because it is too soft and delicate for some processes. 24 carats (24K) correspond to 999.9 grams of gold per 1000 grams of total alloy. 24 karat gold equals pure gold.
The gold most commonly used for jewelery and goldsmith products is 18 karat gold. Its fineness corresponds to 750 thousandths of pure gold, thus maintaining a large part of its gold value as it is composed of 75% pure gold. 18 karat gold is gold which for 24 grams of alloy has 18 grams, or 75.01%, of "pure gold". This gold is also called 750/1000 gold.
History
The specific relationship is borrowed from Latin silique which designates, in the code of Justinian, a silver coin, worth 1 ⁄ 24 of solidus golden. The term siliqua, in particular, derives from siliqua graeca , the seed of the carob tree, which in the Roman weight system is equivalent to 1/6 of a scruple (1/1728 of a Roman pound or about 0.19 grams).
“The man of the new times”, Constantine (396-337), founded the monetary system on solidus , 4.54 gram gold coin. Diocletian (284-305) in turn introduced the solidus weighing 4.8 grams.
The term karat has been applied in modern times to various silver coins based on the assumption that the coins were valued at 1/24th of the solidus gold (which weighed 1/72nd of a Roman pound) and therefore represented a siliqua of gold in value.
Isolde's jewels
Isotta Jewels uses pure 24-carat gold for the creation of its jewels, only for application to third fire when, with a brush, I spread it on the art majolica that will make up my creations.
The necklaces, earrings and bracelets are normally in 925 silver to which I usually apply, through a galvanic process, 18 karat gold (the title immediately following pure gold) which guarantees their correct durability. I make some details such as clasps and hooks in fine and more durable Vermeil gold .
