Diamond etching

Abstract

In order to produce on the table of a diamond gemstone, an information mark which is invisible to the naked eye using a x10 loupe, an ultraviolet laser having a wavelength of 193 nm is used in association with a mask irradiate the surface of the stone at a fluence of less that 2 J/cm 2 per pulse and with not fewer than 100 pulses, in the presence of air which reacts with the diamond and causes the mark to be formed without any darkening which is visible when viewing a microscope.

We claim  
     
         1 . A diamond gemstone having a polished facet in which an information mark has been produced which is invisible to the naked eye aided with a x10 loupe, displays no substantial darkening and does not detract from the clarity grade of the diamond gemstone, said mark being defined by one or more recesses in the diamond gemstone produced by removal of diamond material by irradiating the facet with radiation having a wavelength shorter than about 400 nm in the presence of a reagent which reacted with the irradiated portion of the facet and caused the one or more recesses to be formed in the facet.  
     
     
         2 . A diamond gemstone having an information mark in a polished facet of the diamond which mark is defined by one or more recesses in the diamond gemstone, is invisible to the eye, and was produced by removal of diamond material by irradiating a portion of the facet surface with radiation having a wavelength shorter than about 400 nm, in the presence of a reagent which reacted with the irradiated portion of the facet surface and created said one or more recesses, there being no substantial darkening in the formed mark.  
     
     
         3 . A diamond gemstone having an information mark in a polished facet of the diamond which mark is defined by one or more recesses in the diamond gemstone, is invisible to the naked eye, and was formed by removal of diamond material by irradiating a portion of the facet surface with radiation having a wavelength shorter than about 400 nm, in the presence of a reagent which reacted with the irradiated portion of the facet surface and created said one or more recesses, the formed mark being such that it does not detract from the clarity grade of the diamond.  
     
     
         4 . A diamond gemstone having a polished facet bearing an information mark in the facet, which mark is defined by one or more recesses in the diamond gemstone, is invisible to the naked eye, and was formed by removal of diamond material by irradiating a portion of the facet surface with radiation having a wavelength shorter than about 400 nm, the fluence at the portion irradiated being not more than about 3 J/cm 2  per pulse and not fewer than about 100 pulses being used per portion irradiated, in the presence of a reagent which reacted with the irradiated portion of the facet surface and created said one or more recesses, the formed mark being such that it does not detract from the clarity grade of the diamond.  
     
     
         5 . A diamond gemstone having a polished facet bearing an information mark which is defined by one or more recesses in the diamond gemstone, is invisible to the naked eye, and was formed by removal of diamond material by irradiating a portion of the facet surface with radiation having a wavelength shorter than about 400 nm, in the presence of a reagent which reacted with the irradiated portion of the facet surface and created said one or more recesses, the fluence of the irradiation being below the level at which the formed mark detracts from the clarity grade of the diamond.  
     
     
         6 . A diamond gemstone having a polished facet bearing an information mark which is defined by one or more recesses in the diamond gemstone, is invisible to the naked eye, and was formed by removal of diamond material by irradiating a portion of the facet surface with radiation having a wavelength shorter than about 400 nm, in the presence of a reagent which reacted with the irradiated portion of the facet surface and created said one or more recesses, the fluence being below the ablation threshold of the diamond and being below the level at which substantial darkening is caused to be present in the formed mark.  
     
     
         7 . A diamond gemstone having a polished facet bearing an information mark defined by one or more recesses in the diamond gemstone, formed by removal of diamond material by irradiating a portion of the facet surface with radiation having a wavelength shorter than about 400 nm in the facet, the fluence at the location irradiated being not more than about 3 J/cm 2  per pulse and not fewer than about 100 pulses being used per location irradiated, in the presence of a reagent which reacted with the irradiated portion of the facet surface and created said one or more recesses thereby causing the mark to be formed in the facet.