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.
A 3mm diamond may imply its dimension at the girdle. If the girdle is on a round diamond, this diamond may measure in the range of 1/10th of a carat.
The size of these two objects is exactly the same: 5mm.
Both Asscher cut and Princess cut diamonds have at least one measurement that is 5mm, and both with this perimeter weigh in the one carat range. ('Square' diamond is a description for a rather generic cut.) A certified gemologist can give you an exact weight for your diamond.
If the diamond is a round brilliant cut, the 3mm measurement at the girdle indicates that the diamond weighs about 1/10th of a carat, or .10 carats.
Your answer depends on the cut you are measuring. If the gem is a round cut, the carat weight will be about .10 carats.
3mm to 5mm thick
A 3mm diamond may imply its dimension at the girdle. If the girdle is on a round diamond, this diamond may measure in the range of 1/10th of a carat.
3mm.
You're attempting to determine the weight of a stone given its measurements, which can not be accurate, since the two units of measurement are different. Roughly, however, if the stone is round, it may weigh between .40 and .50 carat, if the 5mm measurement is at the girdle of the diamond.
The 5mm measurement of a diamond is at the girdle. A round diamond with this measurement weighs between .40 and .50 carat. An emerald cut, princess cut or other cut will have a different measurement or series of measurements. Depending on the cut of the diamond, the 5mm space may or may not 'fit'.
The size of these two objects is exactly the same: 5mm.
A grain of suger is 1mm, so 3 grians is equal to 3mm.
show me an actual size circle of 3 mm
DVD and CD drives use the same screws. They are 5 mm long , 3mm thick, with a .5mm thread pitch.
5mm
A one-half carat diamond, in a round brilliant cut, measures about 5.2MM at the girdle.
Both Asscher cut and Princess cut diamonds have at least one measurement that is 5mm, and both with this perimeter weigh in the one carat range. ('Square' diamond is a description for a rather generic cut.) A certified gemologist can give you an exact weight for your diamond.