Geology Home Page physical geology historical geology planetary gems
Roger Weller, geology instructor
by Melissa Richards
Cubic Zirconia is known as a substitute for a diamond, this is
because of its hardness and great fire. In recent years cubic zirconia has been
recognized as a gorgeous gem in its own right. This gemstone is a beautiful and
synthetic that is durable and inexpensive. Cubic zirconia comes in many colors.
Cubic zirconia possesses a less sparkle but has more flashes of
the rainbow. It is very hard but not quite hard as a diamond but can still
scratch glass. Cubic zirconia is measured in carats but a more accurate
measurement would be in millimeters. Cubic zirconia is heavier, weighing
seventy-five percent more than diamonds. Another great difference between cubic
zirconia and diamonds is that diamonds are thermal conductors while cubic
zirconia is a thermal insulator.
So what made it possible in the 1970s to produce
cubic zirconia? That would be the invention of the microwave. The process to
make cubic zirconia starts with the chemicals. Chemical reactions involved in
making these gemstones forces the raw zirconium metal to be combined with
oxygen. Two other components involved are calcium and yttrium, they act as
stabilizers. This is to ensure that the metal and oxygen react and create the
required crystalline structures.
Then we have the heating process. The required temperature to
affect the reaction is more than 4892 degrees Fahrenheit. The combined chemicals
are placed into an industrial microwave. Once the microwave starts, the mass of
chemicals will then heat up from inside out. The outer layer hardens and remains
cool while the inside turns into a molten mass.
Next we need to harvest the gems. After the heating stage in
complete, the “melt” as it is known, is left to cool gradually under controlled
conditions. As they cool, the crystals of cubic zirconia form from molten core
of the melt. Once they are fully cooled they can be cut into the required shapes
what is cubic zirconia used for? Cubic zirconia is used to substitute diamonds.
They are less expensive and almost look like real diamonds. They are used to
make jewelry. For example, many engagement rings are cubic zirconia.
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