R206 Sample ID R206 • Cabinet B obsidian 105.2cm W x 31.5cm H x 67.8cm D • 292g Sample TypeRockRock QualityIgneousRock TypeExtrusive CompositionFelsicTextureGlassyColor Index Clast SizeAcid ReactionMohs Hardness 6 large rectangular chunk of stone with many little Conchoidal fractures running along the edges. entirely glassy except for the far flat end that is raw and dull. Description of Mohs scale here