Glass tiles are pieces of glass formed into consistent shapes. Glass was
used in mosaics as early as 2500 BC, but it took until the 3rd Century
BC before innovative artisans in Greece, Persia and India created glass
Whereas clay tiles are dated as early as 8,000 BC, there were
significant barriers to the development of glass tiles, included the
high temperatures required to melt glass, and the complexities of
mastering various annealing curves for glass.
In recent years, glass tiles have become a popular field and accent
tiles. This trend can be attributed to recent technological
breakthroughs, as well as the tiles’ inherent properties, in particular
their potential to impart intense color and reflect light, and their
imperviousness to water.
Glass in tile introduces complexities to the installer, as glass is
more rigid than ceramic or porcelain tile, so glass tiles break more
readily under the duress of substrate shifts.
Smalti tile, sometimes referred to as Byzantine glass mosaic tile,
are typically opaque glass tiles that were originally developed for use
in mosaics created during the time of the Byzantine empire.
Smalti is made by mixing molten glass with metal oxides for color;
the result is a cloudy mixture that is poured into flat slabs that are
cooled and broken into individual pieces. The molten mixture can also be
topped with gold leaf, followed by a thin glass film to protect against
tarnishing. During the Byzantine era, Constantinople became the center
of the mosaic craft, and the use of gold leaf glass mosaic reached
perhaps it greatest artistic expression in the former seat of the
Orthodox patriarch of Constantinople, the Hagia Sophia.
Traditional smalti tiles are still found today in many European
churches and ornamental objects; the method is also used by some
present-day artisans. In the 1920, mass production methods were applied
to Smalti tile manufacturing, which enabled these tiles to find their
way into many middle class homes. Instead of the old method of rolling
the colored glass mixture out, cooling and cutting, the new method
called for molten liquid to be poured and cooled in trays, usually
resulting in 3/4 inch chicklet-type pieces. 
Since the 1990’s a variety of modern glass tile technologies,
including methods to take used glass and recreate it as ‘green’ tiles,
has resulted in a resurgence of interest in glass tile as a floor and
wall cladding. It is now commonly used in kitchens, spas and bathrooms.
And while smalti tiles are still popular, small and large format glass
products are now commonly formed using cast and fused glass methods. The
plasticity of these last two methods has resulted in a wide variety of
looks and applications, including floor tiles
In the late 1990s, special glass tiles have been coated on the back
side with a receptive white coating. This has allowed impregnation of
heat-transfer dyes by a printing process reproducing high resolution
pictures and designs. Custom printed glass tile and glass tile murals
exhibit the toughness of glass on the wearing surface with photo-like
pictures. These are especially practical in kitchens and showers, where
cleanser and moisture resistance are important.