A layer of lanthanum boride of stoichiometry LaB.sub.x where x is between 9 and 12 is deposited on substrate, for example a stainless steel watch dial, and subsequently treated with a laser, such that the portion(s) of the layer treated with the laser change colour according to the laser power. This produces multicoloured surfaces having high resistance to corrosion and abrasion. The layer of LaB.sub.x is deposited by PVD and by cathode sputtering, using a LaB.sub.6 target of purple-violet colour, such that the colour of the deposited layer differs from the colour of the target. The laser treatment at specific powers changes the stoichiometry of the layer in the treatment portions, such that the colour of these portions changes according to the stoichiometry obtained. At higher powers, the laser will remove the layer of LaB.sub.x. Thus the colour of the treated portions is determined by the material of the substrate.

The invention relates to a method for manufacturing a composite component of a timepiece or of a jewelry part, the composite component comprising a porous ceramic part and a metallic material filling the pores of said ceramic part, said method comprising the steps of: providing a porous ceramic preform of the component, providing a metallic material, heating the metallic material to a temperature higher than the melting point of the metallic material, filling the pores of the ceramic preform with the molten metallic material, cooling the metallic material and the ceramic preform to obtain a solidified metallic material in the pores of the ceramic preform, and applying finishing treatments to obtain the composite component,

wherein said porous ceramic preform consists essentially of a material selected from the group consisting of Si.sub.3N.sub.4, SiO.sub.2 and mixtures thereof, and said metallic material is selected from the group consisting of gold, platinum, palladium metals and alloys of these metals.

The invention relates also to a composite component of a timepiece or of a jewelry part comprising a porous ceramic part and a metallic material filling the pores of said ceramic part, wherein said porous ceramic part consists essentially of a material selected from the group consisting of Si.sub.3N.sub.4, SO.sub.2 and mixtures thereof, and said metallic material which is selected from the group consisting of gold, platinum, palladium metals and alloys of these metals.

A non-magnetic watch component (1) comprising a substrate (4) made of a copper alloy, wherein at least one part of the substrate (4) has a surface layer (5) including Cu.sub.xTi.sub.y intermetallics, and a method for manufacturing this watch component.

A component intended for internal parts or the movement of a timepiece or piece of jewellery includes a substrate coated at least partially with a black coat including aluminium oxide.

Method of manufacturing a watch component (10) for a timepiece, wherein it comprises a first stage of manufacturing a watch component (10) comprising a first surface (1), in which there is arranged at least one recess (20), that is to say a surface recessed from the first surface (1), and wherein it comprises a second finishing stage the watch component, leading to a change in the surface condition, more particularly the roughness, more particularly measured by the parameters Ra and/or Str, and/or the gloss, of the first surface (1) but not of the at least one recess (20) or of a portion exclusively of this at least one recess (20).

A method of making a decorative article (1) such as a jewellery piece, the article comprising a body (2) having a decorative layer (5) and an element (3) set into the body. The method comprises: providing an element that is at least partially coated with a removable layer (4), setting the element into the body, coating the element and the body with the decorative layer, and removing the removable layer and the decorative layer from the element.

An external part including a substrate and a coating composed of the following successively superimposed layers; an opaque or semi-opaque reflective layer, configured to have a reflectance of at least 90% for wavelengths including between 600 nm and 780 nm, a transparent or semi-transparent layer, having a refractive index to include between 1.45 and 2.8 for a wavelength of 630 nm, an absorbent layer, the layers giving the coating a predetermined interference colour.

Methods, apparatus, and systems for fabricating diffractive structures on gemstones for high optical performance are provided. In one aspect, a method includes obtaining a plurality of gemstone characteristics of a gemstone, determining that the gemstone exhibits each of the plurality of gemstone characteristics within a respective predetermined range, identifying a diffractive structure setting associated with a combination of the respective predetermined ranges for the plurality of gemstone characteristics, and fabricating diffractive structures on the gemstone according to the diffractive structure setting.

The present invention relates to a covering element for a portable object made of a first material, the first material being a ceramic material having a first color, characterized in that the surface of said covering element is at least partially treated so as to exhibit at least one conversion having a different color from the first color.

A timepiece or jewelry component comprising a substrate and at least one decoration joined to the substrate, wherein it comprises a transparent coating covering at least one part of the substrate and at least one part of the decoration, the coating changing the perceptible color of the substrate without changing the perceptible color of the at least one decoration.