Ruby Carat Weight

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How the Size of a Ruby Affects its Value

In the wholesale gem trade, rubies are sold on a price per carat basis.  Therefore, it would make sense that a 5 carat ruby would cost more than a 1 carat ruby, all else being equal.  However, an aditional factor is that it is rarer to find a 5 carat ruby than a 1 carat ruby.  Therefore, not only is the total price higher, but the price per carat is also higher because of the added rarity factor.

For example, a 1 carat ruby of excellent quality might cost $1000.  A 5 carat ruby of the same quality would NOT cost $5000 (5 X 1), rather it might cost $10,000.

Here is a comparison of rubies.  They have similar color, so we can see how their size affects their value. Note: We are comparing only the main stones, not their settings.

Very small: Rubies of this size are not rare.  By themselves, they would be worth less than $100.	Average: This size ruby (about 1 ct.) is more valuble but still easy to find.  It would cost about 2 or 3 times the value of the stones to the left.	Large: Rubies this size (over 3 carats) are very rare.  A stone of this size can cost between 7 and 10 times the price of the one before.	Very Large: Rubies of this size (over 7 carats) usually belong to queens or in museums.  The price of one would be 2 to 4 times the value of the previous ruby.