Metal
Metal based glasses are also very common but more so with adults. They are harder to break and have a more classical appearance to them. They cannot be as easily coloured as plastic glasses can be. Most metal glasses are encased in a plastic frame so they can have a particular design to them but they aren`t as breakable as a normal fully plastic frame.
The alloy (a mixture of different metals) most
commonly used in the production of glasses is Monel. This is the most commonly
used metal but a very small percentage of people have an allergic reaction of
the sorts to this particular alloy. Their skin chemistry doesn`t agree with the
alloy and spots may appear around the area of the glasses frame.
Other metals can be
used to make glasses such titanium. Its sliver-grey a metal that's lightweight,
durable, strong and corrosion-resistant. It has been used for everything from
the Gemini and Apollo space capsules to medical implants such as heart valves.
Metal glasses: http://www.snazzyspecs.co.uk/cheap-designer-glasses-gfx/uploads/mens-reading-glasses-G635-metal-frames.jpg
NEXT WEEK: Unusual
frame materials.
