>. I believe Pyrex > is a "borosilicate" glass. ... Pyrex composition: SiO2 (79.6%), B2O3 (12.5%), Na2O (3.72%), Al2O3 (2.4%) and K2O (0.02%). Glass transition temperature: 530oC Vladimir. Outgoing mail is checked by AVG anti-virus system (http://www.grisoft.com). _______________________________________________ ATM mailing list http://www.atmlist.net/