A groove engraving device and a groove engraving method are provided. The groove engraving device includes: a processing chamber for containing a piece to be processed, a cutter for groove engraving on the piece to be processed, a clamping mechanism for clamping the piece to be processed, a driving mechanism for driving the clamping mechanism to rotate, and a temperature controlling device for controlling a temperature inside the processing chamber to be within a preset temperature range. The clamping mechanism and the cutter are disposed inside the processing chamber, and the clamping mechanism is rotatable with respect to the processing chamber. The temperature controlling device is disposed inside the processing chamber. The groove engraving device can improve the processing efficiency and quality of the groove engraving on the piece to be processed.

A groove engraving device and a groove engraving method are provided. The groove engraving device includes: a processing chamber for containing a piece to be processed, a cutter for groove engraving on the piece to be processed, a clamping mechanism for clamping the piece to be processed, a driving mechanism for driving the clamping mechanism to rotate, and a temperature controlling device for controlling a temperature inside the processing chamber to be within a preset temperature range. The clamping mechanism and the cutter are disposed inside the processing chamber, and the clamping mechanism is rotatable with respect to the processing chamber. The temperature controlling device is disposed inside the processing chamber. The groove engraving device can improve the processing efficiency and quality of the groove engraving on the piece to be processed.

The invention discloses a round or a heart shaped gemstone (FIG. 1) (FIG. 8) visually encompassing a heart shape (FIG. 7,15:AD) within, and its method of manufacture. The gemstone comprises of an upper double crown table facet (A), a lower pavilion (C) with a culet (D) at its lower tip, and a girdle (B) separating the upper crown table facet from the pavilion. The pavilion (FIG. 1) comprises of pavilion main facets, lower girdle facets and short half facets. The short arms (P) of the kite shaped pavilion main facets meet at the culet, long arms (Q) meet at 1.sup.st points (R) and the short arms and long arms of each pavilion main facet meet at 2.sup.nd points (S) at specific girdle depths. The lower girdle facets (L) and the respective short half facets (T) are faceted from the lower girdle facets at 1.sup.st pavilion angles along a cable (R) joining the 1.sup.st points. The 2.sup.nd pavilion short half angles (Z) along a cable joining the 2.sup.nd points of the pavilion main facets are less than the 1.sup.st pavilion angles. The girdle depth of the 1.sup.st point of one pair of symmetrical pavilion main facets is 0.5% to 10% less than the remainder pavilion main facets.