The EightStar Diamond Company cuts diamonds commonly called EightStars. These are one of the candidates for the best cut round diamonds in the world, though varying personal preferences mean that no diamond cut can be best in the eyes of everyone. The US company markets EightStar cut diamonds in all parts of the world except Japan. The US company currently obtains rough diamonds from Canadian mines and also has a significant recutting business. It currently produces less than a thousand diamonds a year, all cut at its US head office in California.

The company was founded in Japan by Mr. Tamura based on a diamond cut analysis scope called the Firescope. That led them to develop their uniquely cut diamonds.

Companies attempting to copy them subsequently developed the style of super-ideal cut diamonds called hearts and arrows (H&A), so called because they show a pattern of dark arrows when viewed from the crown/upper side and hearts when viewed from the pavilion. This generic type of diamond cut currently commands a price premium in the US, reflecting their superior optical performance and greater cutting weight loss compared to standard ideal cut and non-ideal cut diamonds.

The EightStar cut differs from the generic H&A diamonds in several trade-secret ways, which serve, among other things, to cause more light to be reflected at the edges of the diamond, leading to a somewhat larger look. In recent years the existence of a scalloped instead of traditional girdle pattern has become relatively well known. This is one of the factors leading to their distinctive appearance and a price premium greater than that of generic H&As. Competitors continue to strive to emulate their cut.

The American Gemological Society (AGS) is the US lab which has the most widely accepted in the US cut grading standard for round brilliant cut diamonds and it has entered into an agreement with EightStar to develop technology to show the cut quality of round and non-round diamonds. This may eventually lead to the AGS taking some non-round diamond grading business from the Gemological Institute of America (GIA), as its current standard did for rounds.

In Japan only, the marketing also reflects the religious symbolism of the mandala (eight starred) pattern. The US company covered by this article started out as an offshore cutting operation for them.

External links

• EightStar Diamond Company
• American Gemological Society
• Gemogical Institute of America
• SF Gate 2004