The fact is that according to the then socio-political settings, delivered abroad could only absolutely flawless in quality product without any defects. This was to once again emphasize the advantages of the socialist economic model. The same is true of the precious stones. However, absolutely whole diamonds come across very rarely, in the vast majority of stones have any defects: cracks, chips, nicks, etc. The Soviet school of cut required that all these defects were corrected, even if it has to significantly reduce the weight of the stone. Therefore diamonds gets really perfect and without any defects, although this is often achieved at the cost of a sharp decrease in mass (and therefore cost).
Foreign same cutters do not even admit the thought that for the sake of getting rid of a tiny, almost invisible cracks or the same cleavage can volunteer to go on a major material loss. So they tried to get rid of when cut only on the material, visible defects, rapidly deteriorating appearance of the stone and, accordingly, its price.
The cost price of a diamond, the cut on the Soviet (or Russian) standard is quite high. It is significantly higher than the cost of stone, faceted in Western Europe, Israel, the commercial type with a maximum mass conservation. But during the Soviet era, when the issues of ideology and prestige often take precedence over economic expediency, the Soviet diamonds in great demand because it serves a guarantee of the highest quality. In addition, the approved type of cut GOST allowed maximize the brilliance of the stone, which also attracts buyers.
Although the Soviet era long past, this type of cut is still very popular. Many world famous companies that sell jewelry, willing to use Russian diamonds.