In 1984 I got my Firescope which was based on Mr. Okuda from Japan's 1970's invention. I designed the Ideal-Scope as a portable version for my businesses diamond buying. The 10x lens has a 'hot pink' reflector in front of the diamond so you can judge how much of the red / pink light refracts back from the diamond.

The redder the diamond the more light is returned. White areas in a diamond show light transmitted from behind the diamond; this is called leakage - the enemy! The blackness of the lens mimics an observer's head which blocks out some light sources.

The most brilliant diamonds look bright pink/red with a black star and minimal white or pale areas. Most ideal cuts have small 'V' shaped white leakage features at the girdle. This is not bad.

Diamonds with perfect symmetry and good proportions show a black eight-pointed star. Hearts and Arrows (and H&A's viewers) was a by-product of Mr. Okuda's discovery.

Around 80% of round diamonds would be rejected with an Ideal-Scope by anyone after just a few minutes practice. It was also instrumental in the development of HCA.

Scientists from Moscow Stat Uni. have computerized the Ideal-Scope; DiamCalc and free Gem Adviser ray tracing program lets you see virtual ideal-scope images of 3D scanned diamonds.