History & Introduction
Spinel as a gemstone is hard vitreous magnesium aluminum oxide that has been used
as a gemstone for centuries. In the past the beauty of spinel because it was mistook
by sapphire and ruby. However, spinel is identified as a gemstone that is worthy
of appreciation in its own right. Spinel is found in a wide variety of colors, such
as rose pink to rich red; lavender to deep violet; light to deep blue, brown, orange,
yellow, and black.
Spinel got its name either from the Latin word, "spina" that means thorn because
of the pointed crystal form, or the Greek word for "spark", related to its bright
color. Spinel is in fact mined for centuries and one of the most famous historical
spinel gemstones is known as "the Black Prince's Ruby". Alike the name, this gemstone
is in red color, which was thought to be a ruby. Edward, Prince of Wales in 1367
acquired the "Black Prince's Ruby."
Recognize - Spinel is mainly like the other gemstones, such as
ruby and sapphire. But, the difference in spinel from other gemstones is due to
octahedral crystal structure and single refraction. Additionally, spinel has a lower
hardness than ruby and sapphire.
Availability - Spinel comes along with ruby and sapphire, and important
deposits have been found in Myanmar (Burma), Cambodia, Thailand and Sri Lanka (Ceylon).
Other locations where spinel deposits found are Australia, Afghanistan, Brazil,
Madagascar, Nepal, Tanzania, Nigeria, Tadzhikistan, and USA.
Usages - Spinel is considered to be a rare mineral, and because
of the qualities and color it is well substituted as a gemstone. It is cut in whatever
gemstone cuts available, mainly in round and oval cuts, although it is surprisingly
not used for jewelry purposes so much.
Buying Guide
Color - The most demanding spinel gemstones are intense red, followed
by cobalt blue, bright pink and bright orange. Paler colors such as lavender tend
to be more affordable. Other colors are black, mauve, greenish-blue, greyish, pale-pink,
violet-blue, yellow and brown.
Clarity and Lustre - Good quality spinel gemstones should have
no visible additions. The additions typically lower the value of spinel gemstones.
In fact, desirable enclosures can result in asterism (the star effect). Presences
in spinel resembles to its octahedral crystal structure or a human fingerprint.
Spinel has a vitreous luster.
Cut and Shape - Spinel can be seen in faceted shapes such as rounds,
octagons, squares, trillions and fancy shapes, such as pears, ovals and cushions.
Vividly colored spinel gemstones are rare in sizes over 5 carats. Translucent to
opaque stones are frequently cut en cabochon. There are few star spinel cut in en
cabochon to display the asterism.
Treatment - Naturally found spinel is not usually treated but,
synthetic spinel is commonly produced because it can appear similar to a variety
of gemstone types. Mainly the synthetic spinel is separated from natural spinel
by the use of a magnet. Due to the iron content natural spinel shows a weak to moderate
response. Some light-colored and orange spinel is colored by chromium, which causes
it to be diamagnetic (repelled by a magnet). In addition to its natural spinel presents
an octahedral crystal structure. Spinel available naturally are also reputable gem
traders declare products as natural or synthetic.
Gemological Characteristics: