A system of polishing a concave surface of an external piece for a timepiece, including a securing device including a support that carries the piece, and a grinding device including an abrasive mechanism rotatably mounted along a first axis and configured to polish the piece along a first curvature. The securing device further includes a moving mechanism of the support so that the support imparts a back-and-forth motion along a second axis and a contact surface of the abrasive mechanism is curved to polish the piece along a second curvature in addition to the first curvature. The system can be applied to the field of crystals for a timepiece.

A system of polishing a concave surface of an external piece for a timepiece, including a securing device including a support that carries the piece, and a grinding device including an abrasive mechanism rotatably mounted along a first axis and configured to polish the piece along a first curvature. The securing device further includes a moving mechanism of the support so that the support imparts a back-and-forth motion along a second axis and a contact surface of the abrasive mechanism is curved to polish the piece along a second curvature in addition to the first curvature. The system can be applied to the field of crystals for a timepiece.

A method for making and decorating top and bottom surfaces of a transparent timepiece component, the method including: depositing a first decoration on a male pattern; moving the male pattern, covered or not covered by a preform, into an injection chamber and injecting a transparent material therein to coat the male pattern to obtain a compound including the top face with the first decoration, on the bottom face; polymerizing the first compound in the injection chamber and then removing therefrom; depositing another material and/or second decoration in a cavity and held by gravity, and deposited on the top surface via a relative motion in the direction of gravity, to obtain a second compound.

A method for making and decorating top and bottom surfaces of a transparent timepiece component, the method including: depositing a first decoration on a male pattern; moving the male pattern, covered or not covered by a preform, into an injection chamber and injecting a transparent material therein to coat the male pattern to obtain a compound including the top face with the first decoration, on the bottom face; polymerizing the first compound in the injection chamber and then removing therefrom; depositing another material and/or second decoration in a cavity and held by gravity, and deposited on the top surface via a relative motion in the direction of gravity, to obtain a second compound.