Sapphire glass, frequently designated as hardened glass or gem glass, is a transparent or translucent glass material fabricated by fusing silica (SiO2) with other constituents such as alumina (Al2O3). Sapphire glass gains popularity due to its high hardness, resistance to abrasion, and outstanding scratch resistance, and is commonly used in high-end smartphone screens, eyeglasses, and watch glasses.

Although sapphire glass has a hardness equivalent to that of corundum and even greater than that of ordinary glass, this does not guarantee that it will not break. The brittleness of sapphire glass is also one of its basic features, whereby the material will shatter if subjected to an external force that exceeds its tolerance threshold. Additionally, when subjected to a sudden and concentrated force, such as that experienced when falling on a hard surface, sapphire glass will also break. In a multitude of applications, this feature requires particular consideration. To illustrate, in the design of smartphones, despite the use of sapphire glass for the screens, it is still imperative to integrate additional protective layers, such as tempered glass or plastic, to mitigate the impact and minimize the risk of screen damage when dropped.

Additionally, sapphire glass has a relatively high melting point, rendering it more stable than ordinary glass at elevated temperatures and less susceptible to melting. At the same time, the chemical stability of sapphire glass is noteworthy, rendering it resistant to reaction with other substances and exhibiting a robust corrosion resistance. These characteristics collectively enable sapphire glass to maintain stable performance in a range of environments.

Despite the favourable physical and chemical properties of sapphire glass, the high production cost and the difficulties associated with processing limit its potential for widespread application. When selecting a sapphire glass product, designers must consider its durability and cost-effectiveness.

In conclusion, although sapphire glass boasts high hardness and good abrasion resistance, it still possesses brittleness and is prone to breakage when exposed to intense impact. Hence, when designing products incorporating sapphire glass, it is necessary to mitigate the risk of fragmentation through structural design optimization and other protective measures to guarantee that the properties of sapphire can be fully exploited.