Often happens when a buyer is difficult to choose between two diamonds. But there are tricks, fitting this choice, as well as some ideas that can be kept in mind. A buyer who has able to see both the stone at the same time, there is a distinct advantage, namely the possibility to compare stones side by side. It is recommended to consider the two stones together, using such lighting conditions and observations, which do not give advantages to any one of them. The first stones compare in the "platform – to the observer>>. You can change the distance from the eyes to the stones, bringing them into the distance at which a person used to read and consider the various items, ie, 25 – 35 centimeters, and vice versa, removing stones at arm's length. You can even increase the distance from the eyes to the stones, up to a distance of 2-3 meters, in which people view ornaments worn by another person, but experience shows that at this distance little stones are distinguishable from each other.
Interesting effects can be seen shaking rocks from side to side. The distribution of light reflections in the stones of the motion, shaking or rotation begins to change, as in a kaleidoscope of diamonds appear more and more flashes of light, as well as changing the color of colored flares. This phenomenon is called gemologists scintillation is observed when a stone, eyes, or light sources are moving. It is believed that the better the cut stone, the greater the scintillation, but in practice it is difficult to measure quantitatively, and the observer must rely on their experience by choosing a stone that sparkles better and plays with his subjective point of view.