If the diamond is a round brilliant cut, it's slightly larger than 16.3MM, which is the measurement of a diamond weighing 15 carats.
Round brilliant 16 ct diamond has a measurement of 15.94-16.01x9.63 approx. And a pear shape has a measurement of 23.60x13.64x8.09.
You've given the carat weight of a diamond. 'Big', then, is based on the cut of the stone.
A one-third carat diamond weighs one-third of a carat. If the stone is a round brilliant cut stone, it's diameter measurement at the girdle will be about 4.4mm.
0.25 means its the carat of diamond,meaning you have quarter of carat real diamond
Every diamond is valued by its cut, colour, clarity and carat weight. A diamond this large is rare: you may be able to find a comparable carat weight diamond in an auction catalog from Sothebys or Christies.
A carat, in relation to diamonds, is a unite of mass that is equal to 0.2 grams. Meaning a 4 carat diamond weighs just over .8 grams and an 8 carat diamond is 1.6 grams.
One carat weight of diamond weighs .20 grammes, so your diamond is about half that weight, or roughly half a carat.
A 1.00 point diamond is one carat, so a .12 point diamond is a little over 1/10th of a carat.
A diamond is valued by its cut, clarity, carat weight and colour. A local jeweler can show you stones in this category.
A one carat diamond in the round brilliant shape measures aproximately 6.5mm at the girdle. If the diamond is another cut, measurements will be different.
You've given the carat weight of a diamond. 'Big', then, is based on the cut of the stone.
Carat is a weight, so its weight is one tenth of a carat or one tenth of .20 grams.
The diamond weighs .125 carats. Its mm measurements depend on the cut.
An eighth of a diamond carat, if it is a round cut, measures about 3.2mm at the girdle.
If the diamond is an ideal emerald cut with these measurements, the diamond may weigh about one quarter of a carat. Otherwise, you have stated the diamond's 'big' size in measurements.
Depending on the cut, a five carat diamond always weighs five carats. If the cut is round brilliant, the mm measurement at the girdle is about 11.
A forty-point diamond is nearly half a carat, which would be fifty points.
The total weight of all the diamonds combined in the carat total weight equals one half carat -- .50. The mm measurement of each individual diamond does not depend on the total carat weight of the collection.