Hard glass and sapphire are two popular materials used by famous watch brands in the world to make their products. With the majority of customers’ choice today being sapphire glass, many people are wondering about the difference between these two materials and how to distinguish them. The following article will help you understand better!

What is a sapphire watch?
A sapphire watch is a type of watch equipped with a glass surface made from sapphire, giving it a shiny appearance and extremely high hardness. Sapphire glass has the superior characteristics of high hardness, good bearing capacity and absolute corrosion resistance. Besides, glass is also scratch resistant and difficult to break. Because of these advantages, sapphire watches are equipped with high-quality products, sophisticated processing and high prices.

Sapphire glass in watches is produced from aluminum oxide powder through the Verneul process to form Sapphire blocks. The hardness of sapphire glass reaches 9 on the Mohs scale, just lower than diamond in all natural stones.

Sapphire glass watch

Sapphire watch crystals can be divided into three main types:

▶ Thin-coated sapphire: This type of glass has only a thin layer of sapphire on top, so it is very fragile and easily scratched after a period of use.

▶ Thick coated sapphire: With a thicker sapphire layer, the watch can be used for a longer period of time.
▶Solid Sapphire: This is the most durable and high-quality type of glass, often used on expensive watches. If light shines on the surface, it will reflect 7 sparkling colors.

What is a hard glass watch?
One of the most widely used materials in the world for watch crystals is mineral glass (hard glass). Made up of inorganic minerals, this hard glass watch has an ideal hardness, reaching about 6 – 7.5 on the Mohs scale. Although not as hard as sapphire, only hard glass can be re-polished if scratched. With cheaper prices, it is no surprise that watches using mineral glass have become popular in the watch industry.

Distinguish between hard glass and sapphire glass
Based on color
Sapphire watches often reflect a pink or milky white color, and are also often blue. Meanwhile, hard sapphire watches are often blue.

Drizzle water onto the surface
When water is poured onto the sapphire crystal surface of the watch, it maintains a circular shape similar to when water is poured onto a lotus leaf. On the contrary, if water is poured onto a hard glass surface, its shape will no longer be round but will spread out.

Use professional measuring equipment
Professional machines to evaluate density, brightness, refraction, hardness and other technical parameters will be the most accurate method to distinguish between the two types of glass, including sapphire watches.

Should I choose a sapphire watch or a hard watch?
About transparency: Sapphire glass on watches has greater transparency than hard glass. However, when used outdoors in sunny conditions, sapphire glass often glares without the AR anti-glare layer. On the contrary, hard glass does not cause glare even when used outdoors.

Hardness: With the same size and thickness, sapphire glass has better bearing capacity than hard glass. However, on the market today, very few watches are equipped with monolithic sapphire glass, which usually only has a thin layer of coating on the surface, making it fragile. Overall, the bearing capacity of sapphire glass is lower than that of hard glass on watches due to the high cost of producing sapphire glass.

The scratch resistance of sapphire watches is almost absolute, superior to watches using hard glass. With high endurance, sapphire glass can withstand both strong impacts and rubbing with hard objects without scratches. On the other hand, hard glass is easily scratched when exposed to hard objects or collided during use. However, hardened glass can be polished to remove scratches and restore it to like-new condition. On the contrary, with sapphire glass, replacement is the only option.

Sapphire watches cost much more than watches using hard glass. The cost of manufacturing and replacing the sapphire crystal is also similar. In contrast, hard glass is cheaper and is commonly used on many watches today. Replacing and polishing the glass is also much less expensive.

In short, when deciding to buy a watch, we need to consider between sapphire crystal watches and hard glass watches. Each material has its own advantages and disadvantages. If you want the most perfect and sophisticated watch, you should choose sapphire crystal. However, if you don’t care about whether the crystal is sapphire or not, a hard glass watch is also a worthy option.

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