R690 Sample ID R690 • Cabinet B Basalt 7.422cm W x 7.889cm H x 4.267cm D • 284g Sample TypeRockRock QualityIgneousRock TypeExtrusive CompositionMaficTextureVesicularColor IndexDark Clast SizeAcid ReactionMohs Hardness 8 Varying shades of Dark/medium gray to light gray. Vessicles completely cover the surface of the rock. Some white minerals can be found dotting across the surface of the rock. Rock is on the small side, shaped somewhat like a trapezoid. Description of Mohs scale here