Quote Originally Posted by RainyDayWomen1235
It seems pretty hard to me
lol i think you got the wrong idea about 'soft glass' it'll still feel just as hard as other glass, but it's far more fragile.

ā??Hard-glassā? is an acronym for borosilicate glass like Pyrex or Kimax. ā??Soft-glassā? is an acronym for soda-lime glass or a higher expansion type glass, (88-92 COE). Lab glass is generally made from ā??hard-glassā?, (borosilicate), bottles are generally made from ā??soft-glassā? or soda- lime glass.

Borosilicate glass has not only good temperature resistance but thermal shock resistance as well. Borosilicate temperatures at atmospheric pressure are up to 500Ā°C for the strain point. The softening point is over 800Ā° C. Maximum thermal shock resistance is 160Ā°C. Borosilicate can easily handle most lab temperatures and can easily handle 400-450Ā° C for short term service, typically 200Ā° C for normal service. The thermal shock means that a rapid change from cold to very hot or the reverse will cause fractures. Soft-glass or soda-lime bottles have an upper temperature limit of 400-450Ā° C but have very little thermal shock resistance and can break easily when taken from heat to cold temperatures very quickly. In fact they can fracture if taken from sterilization to room temperature too quickly.
^^^taken from^^^
http://www.aceglass.com/faq.php#hardglass