Glass Should Not Be Put In Direct Sunlight

I am asked on a daily basis why does your glass pieces say no direct sunlight?  It says that because when glass is put in direct sunlight it makes prisms and prisms can start a fire. Kind of like a magnifying glass.  It's mostly applies to pieces with a lot of clear glass.  Clear glass makes the most prisms.  Do not put your glass not just my glass in a window or on a window sill.
13th Apr 2015 | Posted by Christine