Fill in the Blanks Science l. 25Online version Complete the sentences using information from lesson 25 by Brunny Duran de Azcue 1 cleavage smelting hardness luster Concrete 1 . is a building material made of sand and gravel . 2 . The way a mineral reflects light is known as . 3 . A measure of how easily a mineral can be scratched is its . 4 . The way a mineral splits is a property called . 5 . Metals can be removed from minerals by a process called .