Older clear-glass Pyrex manufactured by Corning before 1998, Arc International's Pyrexproducts,
and Pyrexlaboratory glassware is made of borosilicate glass.Borosilicate glass was first developed
by German glassmaker Otto Schott in the late 19th century and sold under the brand name "Duran" in 1893.
After Corning Glass Worksintroduced Pyrex in 1915, the name became a synonym for borosilicate glass in the English-speaking world.
Borosilicate glass is created by adding boric oxide to the traditional glassmaker's frit of silica,sand,soda, and ground lime.
Since borosilicate glass melts at a higher temperature than ordinary silicate glass,
some new techniques were required for industrial production. Borrowing from the welding trade,
burners combining oxygen with natural gas were required.
Many high-quality flashlights use borosilicate glass for the lens.
This allows for a higher percentage of light transmittance through the lens compared to plastics and lower-quality glass
The Pamukkale Collection's glasses are from Pyrex and the metal parts are made from antique silver. They come for USA with E-12 and for Europe with E-14 bulb holders.