（vajra） （1） An extremely hard material， which is identified with the diamond or the essential substance of gold; often used as an trope for something hard and indestructible. 'Adamantine.' （2） The vajra， or thunderbolt; it is generally shaped as such， but has other forms. Also， any one of the beings represented with the vajra is called a vajra. （3） An abbreviation of jingangchu 金刚杵 a diamond pounder，' a ritual object in esoteric Buddhism made mainly of iron and copper. （4） An abbreviation for jinganglishi 金刚力士， one who handles a 金刚杵. （5） The thunderbolt of Indra， often called The 'diamond club.' Usually considered as one of the sapta-ratna. （6） An abbreviation of "adamantine absorption" 金刚喻定， 金刚三昧.