There are seven types of gems: Pear, oval, square, brilliant, trilliant, marquise, and unique hearts. Each gem has five colors: green, yellow, blue, white, and red. Find them in the following locations:
In Chapter 4-1 instead of running away from Popokarimu, fight him. Stay away from the stairs while fighting him. The gem will appear after you kill him.
In Chapter 6-3 when fighting Wesker, take down the tower of rocks next to the bridge that collapses at the start of the battle. Climb the rocks to another path next to the central island. You will see the diamond.
Heart of Africa(10,000)
In Chapter 5-3 when fighting Wesker, take him out quickly. The gem is in between the stairs on the first floor in the main room while fighting Jill.
In Chapter 5-3 it is located in the roof of the tunnel right before you reach the room where you fight Wesker and Jill.
In Chapter 1-1 fight off the minions that block your path and you will see it.