Method for marking diamond, mark formed by method and diamond marked according to method

A process of forming an optically non-detectable identification mark (110) includes the steps of applying a mark at a surface of a diamond (200) using a focused ion beam (FIB) write process in order to provide an optically non-detectable identification mark (110), the identification mark is formed by changing the optical property of a part of the diamond material at the outer surface of the diamond to form a mark part; wherein the mark is optically invisible, and wherein the mark is visible by an imaging method that provides an observable contrast between portions of the diamond having altered optical properties and unmarked portions of the diamond. The marking process may help prevent forgery of precious articles and help prevent theft events. The invention further discloses a mark, a diamond and a process for viewing the mark on the diamond. 一种形成不可光学检测的鉴别标记(110)的工艺，包括以下步骤：使用聚焦离子束(FIB)写入工艺在钻石(200)的表面处施加标记，以便提供不可光学检测的鉴别标记(110)，该鉴别标记是通过在钻石的外表面处改变钻石材料的一部分的光学特性形成标记部分而形成的；其中标记是光学不可见的，并且其中，标记通过成像方法是可视的，该成像方法在钻石的具有