Friday, 9 December 2016

Chrysoberyl

What Is Chrysoberyl?

Chrysoberyl is a hard, tough, and durable gem. Although lacking the fire of other gemstones, Chrysoberyl in its various forms can be quite valuable. Most Chrysoberyl gems are yellow, though some are brown, green, or orange. Chrysoberyl is best known for its important varieties Alexandrite and Cat's Eye. Alexandrite is a rare and expensive form that exhibits different colours in natural and artificial light. Cat's Eye is Chrysoberyl that is polished into a cabochon and highly chatoyant, displaying a sharp line of light through the centre of the stone.
Chrysoberyl is a beryllium-aluminium oxide mineral with a chemical composition of BeAl2O4. It is distinctly different from the beryllium-aluminium silicate (Be3Al2(SiO3)6 mineral known as "beryl," although the similar names can cause confusion.

Chrysoberyl is not found in deposits that are large enough to allow it to be used as an ore of beryllium. Its only important use is as a gemstone; however, it excels in that use because of its very high hardness and its special properties of chatoyance and colour change.

The Diverse Gems of Chrysoberyl

Chrysoberyl is best known for its use as a gem. There are multiple varieties of gem chrysoberyl, each with its own name and unique physical properties.
Ordinary chrysoberyl is a yellow to yellow-green to green gemstone with a translucent to transparent diaphaneity. Transparent specimens are usually cut into faceted stones. Specimens that are translucent or with silk are usually cut into cabochons.

Physical Properties of Chrysoberyl

One of the most distinctive properties of chrysoberyl is its exceptional hardness. With a Mohs hardness of 8.5, it is the third-hardest gemstone and the third-hardest mineral that is even occasionally found at Earth's surface. Although chrysoberyl is extremely hard, it does break with distinct cleavage in one direction and indistinctly or poorly in two others. It also has a brittle tenacity.
Most specimens of chrysoberyl are nearly colourless or fall into the brown to yellow to green colour range. Red specimens are occasionally found.
Chrysoberyl often occurs in tabular or prismatic crystals with distinct striations. It also occurs in twinned crystals with distinct star and rosette shapes. These crystals usually persist well and retain their shape during stream transport because of the mineral's exceptional hardness. This makes them easy to identify in gem gravels, but the twinning often interferes with their usefulness as gems.

Chemical FormulaBeAl2O4
ColourRed, Green, Yellow, Orange, Brown, Pink, Gray, Black, Multicolored
Hardness8.5
Crystal SystemOrthorhombic
Refractive Index1.744 - 1.755
SG3.5 - 3.8
TransparencyTransparent to translucent
Double Refraction.009
LusterVitreous
Cleavage1,1 ; 3,2. Often exhibits parting along twinned crystals.
Mineral ClassChrysoberyl

Healing properties of Chrysoberyl

Yellow-green chrysoberyl was referred to as "chrysolite" during the Victorian and Edwardian eras, which caused confusion since that name has also been used for the mineral olivine/peridot, that name is no longer used.
Chrysoberyl is the stone of new beginnings. It brings compassion and forgiveness, generosity and confidence into your life. It aligns the Solar Plexus and Crown Chakras. It blends the mind and spirit together and opens the Crown Chakra which then increases both your spiritual and personal power. 
Chrysoberyl strengthens feelings of self worth and releases useless energy patterns. It will help you see both sides of a problem and help you analyse and come to a decision on the correct path. It encourages forgiveness for past sins that have been done to you or by you. 
If chrysoberyl is used with other crystals it will highlight the cause of a disease. It supports self healing, balances the adrenals and cholesterol. It fortifies the chest and liver. 

Geologic Occurrence

As a beryllium mineral, chrysoberyl only forms under those conditions where large amounts of beryllium are present. This limits its abundance and geographic distribution. High concentrations of mobile beryllium most often occur on the margins of magma bodies during the final stages of their crystallization. Thus, chrysoberyl usually forms in pegmatites and in metamorphic rocks associated with pegmatites. These include mica schists and dolomitic marbles.
Chrysoberyl is also found along with other gem minerals in placer deposits. It is a hard, weathering-resistant mineral with a high specific gravity. These properties allow it to survive in sediments after other minerals have been destroyed by abrasion and chemical weathering.