Often, consumers and sex educators will refer to glass sex toys as being made of pyrex glass even though that is the brand name and not the name of the actual material.
The main constituents in borosilicate glass are boron trioxide and silica. Items made from borosilicate glass are less susceptible to thermal shock than other glass items due to its low coefficients of thermal expansion.
More About Pyrex Glass
Consumers frequently find glass sex toys frightening due to the fear that they will break, but pyrex glass is incredibly sturdy.