The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jul. 31, 2007

Filed:

Mar. 23, 2005
Applicants:

Yoshinori Kawabuchi, Yokohama, JP;

Tamotsu Matsumura, Avase, JP;

Inventors:

Yoshinori Kawabuchi, Yokohama, JP;

Tamotsu Matsumura, Avase, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
A44C 17/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

A cut design of an ornamental diamond and an observation method of the diamond which an observer can perceive a more beauty, are disclosed. The cut design is a round brilliant cut comprising a girdle, a crown above the girdle and a pavilion below the girdle. A girdle height (h) is 0.026 to 0.3 times a girdle radius, a pavilion angle (p) of a pavilion main facet ranges from 37.5 degrees to 41 degrees, and a crown angle (c) of a crown main facet is within a range of satisfying: c>−2.8667×p+134.233 and p<1/4×{(sin(1/n)+sin(1/n·sin))×180/π+180·2c}, wherein n: refraction index of a diamond, π: circular constant, p: pavilion angle in degrees, and c: crown angle in degrees. The cut design of the ornamental diamond provides an observer with plenty of visual-perceptible reflection when the observer watches the diamond above a table facet with a sight line of an angle less than 20 degrees with a vertical line at the center of the table facet.


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