Among solids, the highest melting point is exhibited by

Amorphous solid are any noncrystalline solid in which the atoms and molecules are not organized in a definite lattice pattern. Cations and anions are held together by electrostatic forces to form ionic solids. Pseudo solid is a solid which possesses the property of liquids. Van der Waals forces hold molecules together in a molecular solid. 

Ionic solids have the highest melting point due to strong electrostatic forces of attraction.