Abstract: The present disclosure provides a method of forming a hermetically sealed enclosure that comprises a diamond material. The method comprises providing first and second enclosure components comprising the diamond material and having first and second recesses, respectively, at edge portions. At least one of the first and second enclosure components has a cavity. The enclosure components have respective contact surfaces at the first and second recesses and are shaped such that an outer channel is formed by the co-operation of the first and second recesses when the first and second enclosure components are contacted at the contact surfaces to form the enclosure. The method further comprises bonding a first type of material to at least surface portions of the first and second recesses of the first and second enclosure components, respectively.