Disclosed is a scale-like glass (10) having improved heat resistance and improved chemical durability, which is composed of a glass base material satisfying, as expressed in mass%, 60‰¤SiO2‰¤70, 5‰¤Al 2 O 3 ‰¤15, 1‰¤MgO‰¤10, 10‰¤CaO‰¤25 and 4<；(Li 2 O+Na 2 O+K 2 O)<；9, The temperature difference ”T obtained by taking the devitrification temperature of the glass base material from the working temperature thereof is preferably within the range of 0-200°C. The glass transition temperature of the glass base material is preferably within the range of 560-750°C. It is desirable that the value of ”W, which serves as an index for the acid resistance of the glass base material, is within the range of 0.05-1.2 mass%.
