Method of providing markings to precious stones including gemstones and diamonds, and markings and marked precious stones marked according to such a method

A method of providing an identifiable mark on a portion of a polished facet of a surface of an article and being identifiable by an optical magnifying viewing device, said method including the steps of:

• forming a nano-structure of a two-dimensional or a three-dimensional lattice of a plurality of discrete nanometer sized recessed or protruded entities on a portion of a facet of an article, wherein said entities are arranged within a predefined region of said facet in a predetermined arrangement in relation to each other, and such that an outer interface surface between the facet of the article and air is formed and an inner interface surface between the facet of the article and air is formed;
• wherein said predetermined arrangement of said entities is non-uniform and non-periodic arrangement and the predetermined arrangement of the non-uniform and non-periodic arrangement of said entities provides a change of topography of said lattice due to arbitrary shaped and non-uniform and non-periodic spaced entities, and wherein said entities are sized and shaped so as to cause optical scattering such that upon reflection of incident light, and the distance from the inner interface surface to the outer interface surface is greater than the amplitude of the non-marked portion of said polished facet;
• such that upon reflection of incident light having one or more predetermined wavelengths by said lattice of said entities having said predetermined arrangement at a predetermined angle of incidence to said lattice, interference due to scattering of light from said lattice is induced, such that reflected light has a variation in intensity providing one or more local maxima of one or more wavelengths;
• and
• wherein said mark is invisible to the naked eye and is invisible when utilizing an optical magnifying viewing device under normal light condition, and wherein said mark is identifiable by way of the optical magnifying viewing device inclined at a requisite viewing angle under incident light having said one or more predetermined wavelengths such that a local maxima is detected and wherein said mark has significantly increased and enhanced brightness.