In a hydroxyapatite to be joined to another hydroxyapatite or a bone by laser machining (machining of the bone and the hydroxyapatite includes irradiation of laser light on the bone and irradiation of laser light on the hydroxyapatite), to prevent occurrence of a fracture in a junction and in a peripheral portion of the junction during laser machining, the present invention provides an optimum weight ratio of a cordierite or quartz glass component mixed in the hydroxyapatite. As a mixing ratio of the cordierite or quartz glass component, the cordierite or quartz glass component is mixed at least at a weight ratio equal to or higher than 25.7%.
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