The Holloway Cut Adviser is is a computer algorithm of scoring the cut of Round Brilliant diamonds.
The score represents a diamond's potential visual performance. Visual performance is graded in terms of desirable characteristics; such as, potential Light Return, Fire, Scintillation and Spread. Taking these factors into account, an overall score is produced for a diamond.
Most people prefer stones that rate 1-2 on a scale where: 0-2 Excellent, 2-4 Very Good, 4-6 Good, 6-8 Fair, and 8-10 Poor. Zero is almost impossible since many of the factors conflict.
The HCA is intended to be a Diamond Elimination Tool for eliminating diamonds which clearly lack visual performance and exhibit less desirable levels of light return, but not as a diamond selection tool.
The free simulation software can be found here => Holloway Cut Adviser
Considering all the facts around the algorithm, one can say that a HCA score is very useful free tool. The tool can definately help eliminate what not to buy, for selecting a lovely you should not expect any considerable help. Beauty of a diamond is in the eye of beholder and cannot be judged by adding and subtracting numbers. Every diamond is unique.