You can buy a stone like this from Blue Nile today for a little more than US$500.
A princess cut of one carat measures 5.5mm x 5.5mm; one half carat of this cut measures 4.4mm x 4.4mm. Your diamond is about half way in between these weights, and may weigh about .75 carat. A certified gemologist can give you an exact weight.
Generally, you would write .50 carat to represent a half-carat stone.
Half carat is the term used to measure the weight of the real diamond. A diamond's weight does not define or detract from the fact that the diamond is or is not a real diamond.
One carat weight of diamond weighs .20 grammes, so your diamond is about half that weight, or roughly half a carat.
A one-half carat diamond weighs 100 milligrams = 0.10 gram.
A half carat average clarity pink diamond can cost as much as 5,000 dollars. Pink diamond worth is dependent on size, cut and clarity.
You can buy a diamond of about this carat weight today on Blue Nile and pay between US$4,846 and US$60,820, depending on the cut, its quality, clarity, colour and exact carat weight that you want.
There are no princes on earth who appear to be available for sale, sorry, especially one this small.
A half carat diamond of this cut measures 5.2 mm at the girdle; a .65 carat diamond measures 5.6 mm at the girdle. A certified gemologist can give you the exact carat weight of your diamond.
Depending on the cut, colour, clarity and exact carat weight, you could buy a diamond of about this weight today from Blue Nile and spend between US$17,000 and US$21,000. Then, you'd pay for the setting.
If the diamond is a round brilliant cut, the measurement at the girdle of a diamond of this carat weight measures about 5.2 mm. If the diamond is not a round brilliant cut, the measurement will be different.
1 carat is 0.2g, so 1/2 of a carat equates to a 0.1g gemstone.