Products from rock-crystal are striking in their
beauty. They are able to beautifully refract the rays of light, breaking it
into a spectrum. Not for nothing, people make interior decoration items from
this material. It can be considered a gemstone, as it is quite rare. This fact
determines its high cost.
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| Rock-Crystal |
There is a more cost-effective analog of rock crystal,
which is not inferior in quality and beauty. Crystal glass is
lead-silicate glass containing 13–23% of lead oxides and up to 17% of potassium
oxides. The addition of lead oxide increases the refractive index of glass and
the dispersion of light in it. They are made by fusing lead oxide PbO with
silica, sodium or potassium compounds (soda or potash) and small additions of
other oxides.
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| Lead Glass |
Lead glass is more expensive than lime glass, but it
melts more easily and is easier to manufacture. It has an increased density, transparency,
refraction and shine, but less heat resistance than other types of glass. Due
to the content of lead and a certain selection of angles formed by the edges,
crystal products are distinguished by an unusually bright, multi-color play of
light. They also have a beautiful ringing.
An example of the use of crystal glass can be the
manufacture of chandeliers. It is near the source of illumination that the
faceted stones of crystal reveal their beauty to the full. They, like a prism,
break the rays of light and adorn the room with dozens of small rainbows.