All you need to know about diamonds'carat weight and price

The 4C's, which, if supported by a recognized Certificate, are indispensable as guarantors, protecting us against arbitrariness, protecting us from ignorance and therefore from deception, because a price derives from them. 

A diamond does not weigh much, but it is the weight factor that "weighs" the most on the price of a diamond.

The C of Carat: It is a story of a seed (always in the beginning), the carob seed (name that evolved into carat), fruit of the carob tree cultivated since antiquity, used as a unit of measurement for their uniform size and weight by gold and gemstone merchants. The metric carat has since been defined as being equal to 0.2 grams, or 5 carats = 1 gram. A diamond does not weigh much, but it is the factor that "weighs" most on the price of a diamond, which is otherwise fascinating in relation to weight. 

It is because the price of the material is high that diamonds are weighed with precision.

Diamonds concentrate the most value in the least amount of weight.

1 carat of diamond = 0.2 grams,

1 ounce of gold = 31.1 grams.

The weight of an ounce of gold = the weight of 155 diamonds of 1 carat.  

The value of one ounce of pure gold = approximately $1300,

155 diamonds of 1 carat D IF (pure) at Rapaport reference price = $4.2 million ... . 

There are more Jewish musicians who are violinists than pianists. A violin is easier to carry. Diamonds too, much more easily than a gold ligot, and for values that are much higher.

The diamond is paradoxically the cheapest luxury product:

The diamond is paradoxically the cheapest luxury item because it does not wear out, does not require maintenance and is eternal. A 0.50 carat G VS2 diamond bought three years ago would have cost you €1.60 per day, the price of a coffee drink, and love is for life. 

Not really expensive -everything is relative- and not superfluous: historically the wearing of jewelry is one of the first manifestations of human concerns diverging from simple survival.