1. amorphous the amount of kinetic energy that a material can absorb without breaking 2. cleavage a clean break parallel to planes of weakness in a crystal 3. crystal a non-crystalline solid having no orderly arrangement of molecules 4. fracture a single chemical compound or element that is found in nature 5. hardness a break that does not follow a flat surface, but rather is rough and uneven 6. mineral resistance to being scratched 7. toughness a solid form resulting from the arrangement of atoms, ions, or molecules in definite geometric patterns