EP0891142B1 - Precious stones having tetrahedron structures - Google Patents

Abstract

A precious stone is formed having a plurality of tetrahedron shaped structures (12, 14, 14', 16) disposed on the sides of the stone between the table (18) and the girdle (20). The tetrahedron shaped structures (100, 110, 100', 112) are also provided on the sides of the precious stone below the girdle (20). The tetrahedron structures may be disposed on square shaped precious stones, rectangularly shaped precious stones and emerald cut stones and the tetrahedron shaped structures may be stacked in a vertical orientation on the sides of the precious stone below the girdle.

Description

FIELD OF THE INVENTION

The present invention relates to precious stones having facets disposed thereon and, more particularly, the present invention relates to precious stones having upraised tetrahedron structures formed on the surfaces of the stones.

BACKGROUND OF THE INVENTION

With reference to Fig. 1, conventional precious stones include a table 1, a girdle 2 and notches 7 disposed below the girdle 2, which notches 7 include top and bottom surfaces 6 and 5 respectively.

US-A-4 020 649 describes a precious stone having tetrahedron-shaped structures on surfaces above the girdle. US-A-5 072 549 describes a precious stone having one tetrahedron structure on each of the side surfaces below the girdle and tetrahedron structures on the side surfaces above the girdle.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a precious stone which is aesthetically pleasing.

Another object of the present invention is to provide a precious stone having improved capabilities of reflecting light resulting in a more brilliant stone.

To meet these and other objects, the present invention provides a precious stone having the features of claim 1.

Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of a square shaped precious stone in accordance with the prior art, for example, U.S. Patent No. 4,738,240;

Fig. 2 is a top view of a square shaped precious stone in accordance with a first embodiment of the present invention;

Fig. 3 is a side view of the precious stone of Fig. 2 as seen from any of its four sides;

Fig. 4 is a perspective view of the precious stone of Fig. 2 illustrating two adjacent sides;

Fig. 5 is a top view of a second embodiment of the present invention comprising a precious stone identical to Figs. 2-4 except for being a rectangularly shaped baguette;

Fig. 6 is a side view of the precious stone of Fig. 5;

Fig. 7 is a perspective view of the precious stone of Fig. 5 illustrating two adjacent sides; and

Fig. 8 is side view of a square shaped or a rectangularly shaped precious stone which is identical to the precious stone of Fig. 3 with the exception that each side contains four tetrahedron shaped structures arranged in sequence along the vertical (height) direction thereof, which structures are located below the girdle of the stone.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

With reference to Figs. 2 and 3, a square stone having unique facets according to a first embodiment of the present invention is shown. The table 18 of this stone is the upper most flat surface and the girdle 20 comprises the locus of points on the stone where its circumference is largest.

With line 2-2 as a fulcrum, the precious stone is placed on a grinder or the like and pivoted in a direction of increased grinding using the fulcrum 2-2 as a pivot point such that surface 10 is created. Similarly, the precious stone is pivoted in a direction of increased grinding using the fulcrum 2-2 as a pivot point to create surface 10'. Surfaces 14 and 14' are created in a similar manner. Consequently, surfaces 12 and 16 are also produced. The result of such grinding is a tetrahedron shaped structure disposed between the table 18 and the girdle 20 having an apex (A) along the fulcrum line 2-2. Additional tetrahedron shaped structures are disposed on the other three sides of the precious stone between the table 18, an the girdle 20.

With reference to Fig. 3, the surfaces of the stone below the girdle 20 extend angularly inwardly toward the Z (height) axis of the stone. The surface angle of inclination directly below the girdle 20 is at a first constant angle for a predetermined distance (D1), then a steeper angle for a second predetermined distance (D2), and then still a steeper angle for a third predetermined distance (D3), etc. Surfaces 110, 112, 100 and 100' are produced in the same manner as described hereinabove using fulcrum line 3-3 as a pivot point to create a tetrahedron shaped structure on a surface of the precious stone below the girdle 20. Similarly, surfaces 114, 118, 116 and 116' are produced to form still another tetrahedron shaped structure on the surface of the precious stone below the girdle 20. Additional tetrahedron structures are disposed on the other three side surfaces of the precious stone below the girdle 20.

The heights of the apexes of the tetrahedron structures are quite small. Nonetheless, by providing these tetrahedron structures, applicants' obtained numerous light reflecting surfaces which reflect light up to the table 18 of the precious stone resulting in a brilliantly sparkling and highly attractive stone appearance.

Figs. 4 and 8 show that three stacked tetrahedron structures may be disposed on any one or all of the four sides of a square shaped precious stone below the girdle 20. Figs. 5-7 show that the tetrahedron structures may be disposed on a precious stone having a rectangular (baguette) shape or an emerald cut stone.

Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.

Claims (5)

1. A precious stone having a table (18), a girdle (20) and a plurality of side surfaces below the girdle arranged symmetrically around a fulcrum line (3-3) that extends perpendicularly to the table (18), the precious stone comprising at least two tetrahedron shaped structures disposed one below the other and in different planes on most of the side surfaces of the precious stone below the girdle (20), each tetrahedron shaped structure is defined by an apex (A) lying along the line which bisects the side surface and having four tetrahedron surfaces (100, 100', 110, 112, 114, 116, 116', 118) sloping away the apex (A) toward respective edges of the plane of the side surface where it is located.
2. The precious stone of claim 1, wherein additional tetrahedron shaped structures (12, 14, 14', 16) are disposed on a side surface located between the table (18) and the girdle (20).
3. The precious stone of claim 1, wherein the stone is square-shaped.
4. The precious stone of claim 1, wherein the precious stone is rectangularly-shaped.
5. The precious stone of claim 1, wherein the precious stone is of an emerald cut.

Images