... , yellow, amber, pink, purple lab use Ground glass joints of borosilicate 3.3 pyrex are used in ... was time-consuming and expensive, or the use of less chemically- and heat-resistant or and glass ... glass bongs.To connect the hollow inner spaces of the glassware components, ground glass joints are ... ends, except for stoppers.Glass ground joints of borosilicate 3.3 pyrex types:Conically tapered jointsBall ...