1 Brands: Tums, Caltrate, and most other brands.  Absorption: Calcium carbonate is alkaline based. It requires extra stomach acid for better absorption, so it is best taken right after meals or with a glass of acidic juice such as orange juice.
Tempered glass is one of two kinds of safety glass regularly used in applications in which standard glass could pose a potential danger. Tempered glass is four to five times stronger than standard glass and does not break into sharp shards when it fails. Tempered glass is manufactured through a process of extreme heating and rapid cooling, making it harder than normal glass.
Heat-strengthened glass is twice as strong as annealed glass while fully tempered glass has typically four to six times the strength of annealed glass and withstands heating in microwave ovens. The difference is the residual stress in the edge and glass surface.