In a method of making an injectant-nonmetallic composite having a fracturable nonmetallic base material: a block of fracturable nonmetallic base material is encased in an investment material to an extent that the block is held together when fractured; the block is fractured; a bonding material is introduced into the fractures created in the block to bond the block together when the block is no longer encased in the investment material; the block is removed from the investment material and encased in a second investment material to an extent that the block is held together when the bonding material is removed from the fractures in the block; the bonding material is removed from the fractures in the block; the block is heated; and a molten injectant is introduced into the fractures and solidified to form an injectant-nonmetallic composite.