Ruby jewelry is said to provide health, happiness and wisdom
for those who wear it. As the birthstone for July, ruby jewelry is a great
gift for birthdays during that month. One historical piece of ruby jewelry
includes the Crown Jewels of England, Edwardes Ruby, which weighs an
impressive 167 carats. Specimens of that size are quite rare and are normally
only found in museums. A 3-4 carat ruby, if of fine quality, is a rare and
very expensive gem by today's standards. Rubies are considered the most
valuable of all gemstones, except for extremely rare colored diamond
varieties.
Interestingly, rubies belong to the group of mineral known as
corundum. Corundum is available in a variety of colors, though only the red
varieties are known as ruby. All other colors are called sapphire. The red
color, from which it derives its name (Rubeus), is caused by trace amounts of
the element chromium. The best shade of red for ruby jewelry is often given
the name "pigeon blood red", but rubies can be any shade of red up
to almost pink. High quality rubies may be referred to as Burma-ruby or
Siam-ruby. A unique variety of ruby includes the Star Ruby. This gemstone has
crystal inclusions of rutile that are oriented in such a way as to cause a
six-rayed star effect, known as asterism. Often cabochon cut, these Star
Rubies make beautiful ruby jewelry pieces.
The Moh's scale of hardness lists ruby, the variety of
corundum, as a 9. While this is the second hardest mineral known to humankind,
it should be noted that it is only 1/140th as hard as diamond, the hardest
natural substance. Conversely, it is seven times as hard as Topaz, number 8 on
the list. While ruby jewelry is an excellent choice because of its hardness
and durability, care must be taken against direct blows, as these may break
the almost always included gemstone. Because of its brittleness, care must be
taken when ruby jewelry is worked on by a jeweler. It is safe to clean ruby
jewelry by steam and ultrasonic cleaning.
