Method of Setting Precious and Semiprecious Stones

1. Field of the Invention

The present invention relates to a method of setting precious and semiprecious stones, applicable to all jewels and more particularly to diamonds. The invention also covers the settings obtained by means of this process.

2. Description of the Prior Art

At the present time the setting of precious stones and diamonds is known but it is very difficult to obtain an invisible setting or a setting which does not adversely affect the value of the stone. Present settings in fact imply the formation of relatively deep notches on the culet of the stones, for receiving metal holding pieces. Thus longitudinal notches may be formed sliding over rails of the mount, or else notches at the angles of the culet receiving metal claws of said mount. In both cases, the notches must be deep in order to provide reliable fixing, but such deep notches cannot be used with diamonds for they destroy the luster thereof and thus adversely affect their value. Such a method is for example described in French Pat. No. 802 367.

The present invention aims then at overcoming such disadvantages by providing a simple and rapid setting method which cannot adversely affect the value of the stones, in particular diamonds whose setting remains invisible and luster unchanged.

In accordance with the invention, on each stone slight notches are formed at the angles of the culet, whose small depth is such that the distance separating the bottom of two opposite notches is very much greater than the width of the table of the stone, the whole of the mounted stones is provisionally held in position by masking their table side then a metal is run so as to form a holding grid on the culet side.

Thus, the metal penetrates into the notches while forming said grid as a single perfectly solid block, the elements of the grid occupying a restricted space placed so that they are invisible on the table side.

Other features and advantages of the invention will be clearer from the following description with reference to the accompanying drawings in which:

FIG. 1 shows an elevational view in section along a diagonal line 2--2 of FIG. 2 of a squared diamond to which the method of the invention is applied;

FIG. 2 shows a schematical plan view from the culet side of a diamond according to FIG. 1;

FIG. 3 is a schematical view in elevation and in section of an assembly of two juxtaposed diamonds; and

FIG. 4 shows a schematical plan view from the table side of an assembly of diamonds.

In these drawings the same reference designate the same elements.

Referring to FIGS. 1 and 2, a jewelery diamond comprises a table 1 of diagonal width 1 with for example two facets 2 and a culet generally referenced 3, normally having facets such as facets 4 and 5. In accordance with the invention, a very slight notch 6 is formed (shown very much enlarged for the sake of clarity) at each corner 8 of the culet formed by the facet 4 of said culet adjacent the girdle 9 which defines the upper part 1, 2 and the culet 3 of the stone. As mentioned above, the notches have a very small depth and the distance L separating the bottom of two opposite notches 6, 7 is very much greater than the diagonal width 1 of the table 1 and does not extend inwardly beyond the first facet 2 adjacent the girdle 9. Such miniaturized notches are advantageously formed using a "laser" so that they have the required fineness and precision.

Referring to FIGS. 3 and 4, for the setting operations, the whole of the mounted stones is temporarily held in position in the desired shape, for example by means of modelling wax in which the culets 3 are inserted whereas the table side of the stones is masked with plaster forming a stable support. Then the wax is removed, which is replaced by a synthetic resin which, by hardening, forms a support block which is then introduced into a molding cylinder known per se in the jewellery trade and in which a metal is run under pressure, for example a gold alloy. The resin is then removed and destroyed, whereas the liquid metal enters into the notches 6, 7 although only slight and forms a thin pad 10 between the facets 4 adjacent the girdle 9 of the juxtaposed stones. The pads 10 thus formed constitute the elements of a metal grid in a single block and, because of the slope of facets 2 as well as the fact that neither the notches already practically invisible in themselves nor the pads are disposed in line with the tables 1 of the stones, the grid thus formed remains invisible from the table side while providing perfectly firm fixing. It is clear that this arrangement has a considerable advantage with respect to the rail or claw mounting methods requiring deeper notches and that it does not adversely affect the value ofthe stones, because of the miniaturization of the notches.

It will of course be readily understood that the present invention has been described and shown by way of explanation which is in no wise limiting and that any useful modification may be made thereto particularly within the field of technical equivalences without departing from its scope or spirit. In particular, although stones of a general square shape have been shown, the method applies to any polygonal shapes of stones.