What does HCA or IS mean?

[cindyvet]

I just got a nice reply from one of you experts, but do not know what the terms HCA or IS are? I am in the medical field , not the diamond field and the terminology is daunting here.
cindy

 

[pricescope]

HCA - the Holloway Cut Adviser: https://www.pricescope.com/cutadviser.asp see also http://www.diamond-cut.com.au/

IS - Ideal-Scope: https://www.pricescope.com/idealscope_indx.asp and http://www.ideal-scope.com