Its oxygen atoms are arranged in a hexagonal close-pack denser than that of quartz, which accounts for its greater hardness in spite of the fact that its bonds are less covalent than those of quartz.
Its oxygen atoms are arranged in a hexagonal close-pack denser than that of quartz, which accounts for its greater hardness in spite of the fact that its bonds are less covalent than those of quartz. Its fine granular form, when mixed with magnetite, is an industrial abrasive called emery, and it is often used as the grit of sandpaper. For 10 points, identify this crystalline form of aluminum oxide, the major varieties of which are topaz, sapphire, and ruby, whose Mohs hardness is defined as nine
Its oxygen atoms are arranged in a hexagonal close-pack denser than that of quartz, which accounts for its greater hardness in spite of the fact that its bonds are less covalent than those of quartz.
{corundum}