R673 Sample ID R673 • Cabinet B Obsidian 5.611cm W x 9.644cm H x 3.299cm D • 164g Sample TypeRockRock QualityIgneousRock TypeExtrusive CompositionFelsicTextureGlassyColor IndexDark Clast SizeAcid ReactionMohs Hardness 6 Wedge like shape that is nearly entirely glassy on one side and the other is mostly raw. Has some scallop like lines in the glass. Description of Mohs scale here