Perspex vs Sapphire Crystal

Because we have all had a good laugh at our last video review and my inability to say Perspex. So I thought I would do a little bit of looking around and find out the differences of Perspex and how Sapphire Crystal is made.

Perspex, or Plexy Glass along with about 20 other different brand names for this product is actually a plastic with a chemical formula of C5H8O2. Its real scientific name is actually Poly Methyl Methacrylate, hence why industry have run with Plexi Glass or Perspex. It is a clear plastic with good impact strength, clarity and UV stability. With high impact strength it is used for other applications like street light covers, ice hockey barriers, and of course watch glass. It is a molten material at around 240 degrees celsius and can be injection molded, or easily extruded into the desired shape. It has one small weakness in that is can be scratched, but not easily. This weakness is offset by its cost, as the cost of plexy glass is significantly cheaper than Sapphire Coated Crystal.

Sapphire Crystal Coating is a very hard, transparent material made of crystallizing aluminum oxide at very high temperatures. Chemically, synthetic sapphire is the same as the natural sapphire, with a chemical formula of Al2O3 used in jewelry, but without the coloring agents that give the gemstone its various hues. About 3% of the worlds production of synthetic crystal goes into the watch industry with the majority of the worlds production going into semiconductors. Apart from being highly resistant to scratching a 9 out of 10 on the Mohls scale, it is also highly resistant to chemicals, making it ideal for use in industries like petroleum, furnaces and other hostile environment industries. Produced at high temperature as molten glass before being cut, ground and polished into the desired shape.

That is just a quick break down of what I know about these two materials. Please if you have any more good information about these two materials and their properties please add it below, in a constructive method. There are a lot of people out there on the forum who just read without asking questions and would like to know about the finer technical issues associated with Oris watches. Here is the starting point and let's build it from, Watch Knowledge 101, I feel like I'm back at uni.


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