Superidealist
Brilliant_Rock
- Joined
- Sep 10, 2003
- Messages
- 655
I've become interested in the history of hearts and arrows diamonds and decided to go to the source to see what I could find out. I emailed a couple of the Japanese labs with the following four questions:
1. What is the history of the Heart and Cupid diamond?
2. Which companies were among the first to cut Heart and Cupid diamonds?
3. Who invented the Heart and Cupid scope?
4. What are the standards for grading Heart and Cupid diamonds?
Mr. Katsunori Hirama of Zenhokyo's diamond grading division was kind enough to provide the following answers (edited for clarity):
1. The Heart and Cupid pattern seen in brilliant cut diamonds was discovered accidentally using the "cut proportion scope" about 15 years ago by Mr. K.Yamashita, President of Mount Gold Co., Ltd. Since then, stones showing this pattern have become popular in the Japanese market.
2. In general, the Heart and Cupid pattern can be seen only in excellent cut diamonds. Therefore, the stones showing this pattern had to be selected from excellent cut stones in the early stages. Once the mechanism of this pattern became clear, some small cutting works in Japan and some subsidiaries or tie-in companies of Japanese jewelery firms in foreign countries began, and are nowadays, specially producing these.
3. The Heart and Arrow scope was invented by Mr. I. Yamashita, by remodeling the proportion scope. The scope and its usage were patented in Japan in November, 1990. Also, another patent for an observing method and apparatus was approved on July 8th, 1994 in Japan and July 4th, 1995 in the US by H. Kobayashi of Taiko Co., Ltd. of Tokyo, Japan.
4. The grading standards for H&C diamonds are not officially decided for the Japanese market and so each appraising organization has its own standard. Of course, we at GAAJ have our own precise standards which can be shown you if you require.
I don't want to bother Mr. Hirama, but if there is anything the Pricescope community would like to ask as a follow-up, he may be willing to answer.
On a related note, here is a PDF file detailing the CGL's standards for grading hearts and arrows.
1. What is the history of the Heart and Cupid diamond?
2. Which companies were among the first to cut Heart and Cupid diamonds?
3. Who invented the Heart and Cupid scope?
4. What are the standards for grading Heart and Cupid diamonds?
Mr. Katsunori Hirama of Zenhokyo's diamond grading division was kind enough to provide the following answers (edited for clarity):
1. The Heart and Cupid pattern seen in brilliant cut diamonds was discovered accidentally using the "cut proportion scope" about 15 years ago by Mr. K.Yamashita, President of Mount Gold Co., Ltd. Since then, stones showing this pattern have become popular in the Japanese market.
2. In general, the Heart and Cupid pattern can be seen only in excellent cut diamonds. Therefore, the stones showing this pattern had to be selected from excellent cut stones in the early stages. Once the mechanism of this pattern became clear, some small cutting works in Japan and some subsidiaries or tie-in companies of Japanese jewelery firms in foreign countries began, and are nowadays, specially producing these.
3. The Heart and Arrow scope was invented by Mr. I. Yamashita, by remodeling the proportion scope. The scope and its usage were patented in Japan in November, 1990. Also, another patent for an observing method and apparatus was approved on July 8th, 1994 in Japan and July 4th, 1995 in the US by H. Kobayashi of Taiko Co., Ltd. of Tokyo, Japan.
4. The grading standards for H&C diamonds are not officially decided for the Japanese market and so each appraising organization has its own standard. Of course, we at GAAJ have our own precise standards which can be shown you if you require.
I don't want to bother Mr. Hirama, but if there is anything the Pricescope community would like to ask as a follow-up, he may be willing to answer.
On a related note, here is a PDF file detailing the CGL's standards for grading hearts and arrows.