adamantine

"He polished the brass doorknob to a high luster."

"Quality of life is usually determined by health, education, and income."

"The incapable student struggled to complete even the simplest assignments. "

"Light penetrates darkness."

"I have a house and a car."

"The ruling party or coalition sometimes dissolves parliament early when the polls are favorable, hoping to reconvene with a larger majority."

"The homeowner secured his house by locking all the doors and windows before leaving for vacation. "

"The saw is coated with diamond."

"The hardness of the diamond makes it ideal for cutting glass. "

"The diamond's adamant nature made it incredibly difficult to cut. "

"If the vase falls to the floor, it might break."

"The impossible of finishing the project by Friday became a reality when everyone worked late. "