I also concern about 35.5 crown angle - too steep.

I'll send this topic to Whiteflash and ask to clarify this

If you are still curious about this diamond you can just call them: 1-877-612-6770.

They are nice and knowledgeable so you'll get all info you need.

I am surprised myself to see this example. As far as I know A Cut Above brand is on of the best and consistent H&A available today. Most of their stones are rated excellent by the HCA.

Don't give up, you already know more than average diamond sales person. There are still plenty of great diamonds out there

Measuring a 3mm stone with a lens designed to measure 20mm diamonds will reduce the accuracy by a factor of three compared to using a lens designed for a 7mm maximum stone diameter.
Another problem is the fact that Sarin proportions often do not add up to an accurate total depth as calculated by dividing depth by diameter. There are several reasons for this, however the solution applied by Ogi is to adjust the other parameters to equal the known weight. This is akin to a surveyor adjusting rise and fall measurements to ‘close the loop’. This approach adds an error to at least one or more of the measured proportions, rather than accepting the best assessments of the instrument. While it is difficult to explain this error, it is one of the likely reasons why all the major laboratories choose Sarin over Ogi.
Used properly a well-calibrated Sarin measures to an accuracy of 20 microns and gives results to within 0.2 degree. This level of inaccuracy will provide significantly different results using the Cut Adviser at Pricescope, but this is a constraint faced by all cut grading systems. The most positive comment that can be made is that the most accurate facet measurement is the pavilion facet angle. This is because it is the longest measurement made and the methods employed measure inclination more accurately. The same method is used for short facets, the inclination is measured and interceptions are plotted, so the shorter the distance between two points on the facet edge being analyzed, the greater the margin for error.