Phazite

From Wikitroid, the Metroid wiki

Phazite is a more durable form of Phazon. It is used extensively by the Space Pirates. With the use of the X-Ray Visor and the Nova Beam, Samus can see through Phazite and fire through it. It is normally blue, but rarely it is red. Red Phazite is used to make armor for Pirate Commanders. No single known weapon can pass through red phazite. It is unkown if red phazite has any connection to the orange phazon found in the Impact Crater.