Crystal glass is a material used to create crystal flasks. It requires level 89 Crafting to turn into crystal flasks, which is not assistable but can be boosted. It is acquired by melting down crystal-flecked sandstone found in Prifddinas and the edimmu resource dungeon, using the robust glass machine in the Ithell Clan district of Prifddinas. Crafting the glass with a glassblowing pipe makes a crystal flask, giving 150 Crafting experience normally, or 180 Crafting experience when crafted in Ithell Clan district when the Voice of Seren is active there. The quest As a First Resort is required to make the crystal glass.