Tips to know about Gems and Semi-precious stones
-     The three qualities of a Gemstone are-Beauty, Durability and Rarity.
-     Gems are classified in to two categories- Natural Gems (Gem minerals and Organic Gems) and Artificial Gems (Synthetic Gems).
-     A Gem is assessed by 4C’s- Colour, Clarity, Cut, Carat weight. The colour should be pure and evenly distributed. The gem should be transparent and there should not be any visible inclusions. The gem should be cut in proper proportion with a proper crown and pavilion. The higher the carat weight, the more expensive the gemstone is.
-      1 carat= 0.2 grams and 5 cts= 1g
-     Often the crystal shape is the characteristic of a gemstone.

All the crystals are divided into seven groups:

1. Cubic- Diamond, Garnet, Spinel
2. Tetrgonal-Zircon
3. Hexagonal-Emerald
4. Trigonal-Sapphire, Quartz, Tourmaline
5. Orthorhombic-Alexandrite, Topaz
6. Monoclinic-Moonstone
7. Triclinic-Turquoise

-     There are some gemstones which are made up of Non-crystalline materials e.g Opal
-     The physical properties of Gems include

1. Hardness- Hardness is the resistance for scratching a Gemstone by another material. The Gemstones are tested on Moh’s scale of Hardness.
2. Specific Gravity-The density of a Gemstone is compared in relative to the density of water. E.g Ruby-4; Quartz-2.65.
3. The Gemstones are also tested using their optical properties e.g. Refractive Index using Refractometer, double refraction using Polari scope etc.
4. The gemstones can also be identified by studying their Spectrum. The white light is made out of several colours as seen in a rainbow. Some elements in the gemstone absorb some of these colours and the remaining colours produce the colour of the gemstone. Through the Spectroscope these absorbed colours are seen as Dark lines or bands creating a pttern which helps in identifying the gem variety. Some of the common Gemstones and their characteristics are given below for easy identification:

• 1. Ruby
     Colour-Bright red, purplish red, deep-pink
     Composition-Al2O3
     Hardness-9
     Specific Gravity-4
     Refractive Index-1.76-1.78
     Found in Burma, Thailand, Tanzania, Vietnam
     Stimulates nurturing emotions and economic stability. Excellent for shielding from psychic attacks and gathering and amplifying energy.
  2. Sapphire
     A number of varieties are available:
     Blue Sapphire
     Star Sapphire
     Padparadscha
     Yellow Sapphire
     Pink Sapphire
     White/colourless sapphire
     Orange sapphire
     Green sapphire
     Colour changing sapphire
     Purple sapphire
     Colour-Bright red, purplish red, deep-pink
     Composition-Al2O3
     Hardness-9
     Specific Gravity-4
     Refractive Index-1.76-1.78
     Found in Sri Lanka, Burma, Thailand, Tanzania, Madagascar, India, Australia
     Promotes light, pure emotions - purity of mind, serenity, joy, and peace. Opens the mind to beauty and love. Clears the mind of unwanted thoughts.
  3. Cat’s Eye
     Colour-pale yellow, Brownish, or Greenish stones
     Composition-BeAl2O4
     Hardness-81/2
     Specific Gravity-3.72
     Refractive Index-1.74 to 1.75
     Found in Sri Lanka, Brazil, Russia, Burma, India, Tanzania
  4. Emerald
     Colour-Bright Green
     Composition-Be3Al2(SiO3)6
     Hardness-71/2
     Specific Gravity-2.8
     Refractive Index-1.56-1.59
     

     Found in Colombia, India, Nigeria, Brazil. Emeralds always contain visible inclusions and they are often treated with oil or resins to make them strong.

     Emerald is the gem that Mercury loves. Astrologically, for the people born under the signs of Gemini and Virgo, the Emerald is very beneficial and is known as Gem of life.

  5. Aquamarine
     Colour-Blue, greenish blue
     Composition-Be3Al2(SiO3)6
     Hardness-71/2
     Specific Gravity-2.8
     Refractive Index-1.56-1.59
     Often the green stones are heated to produce the blue colour.
     Improves sight, sharpens the mind, calms and clarifies emotions.
  6. Diamond
     Colour- Colourless or coloured (Fancy)
     Composition-Carbon
     Hardness-10
     Specific Gravity-3.52
     Refractive Index-2.42
     Found in South Africa, India, Australia, Canada, Namibia, Zimbabwe, Zaire
     Manifests abundance. Used in conjunction, it strengthens the properties of other stones.
     Colour Grading of Diamonds
     Clarity Grading of Diamonds
  7. Tiger’s eye
     Colour- Brownish body with Asbestos fibers
     Composition-SiO2
     Hardness-7
     Specific Gravity-2.65
     Refractive Index- 1.54-1.56
     Clear thinking, helps in manifesting will, courage, and confidence.
  8. Topaz
     Colour- Pink, Golden, Colourless, Blue, Red, Green
     Composition-Al2(F,OH)2SiO4
     Hardness-8
     Specific Gravity-3.53
     Refractive Index- 1.61 -1.68
     Found in Brazil, Sri Lanka, Nigeria, Burma. Often colourless stones are turned to blue by irradiation.

     Soothes physical pain, promotes peace and calms emotions, as well as promoting forgiveness. Promotes individuality, self-confidence, and creativity. Counteracts negative emotions.

  9. OPAL

     Opal displays the play –of-colour effect. There are different varieties of Opals. In the Precious Opal, the play of colour is seen on a black back ground. In White Opal, the play of colour is seen on a white background. In Water Opal, the play of colour is in a transparent to translucent body. The Fire Opal is yellowish orange to red and transparent to translucent stones.
     Composition-SiO2 and water
     Hardness-6
     Specific Gravity-2.10
     Refractive Index- 1.45
     Found in Australia, Brazil

     Awakens and helps understanding of psychic intuition and mysticism. Encourages living authentically in feeling and action, with faithfullness and loyalty. Helpful for eyesight and during childbirth.

  10. Peridot
      Colour-Yellowish-Green, Green
      Composition-(Mg, Fe)2SiO4
      Hardness-61/2
      Specific Gravity-3.4
      Refractive Index- 1.65-1.69
      Found in Burma, Pakistan
      Balances your emotional mind and calms emotional storms. Aids digestion and insomnia and increases psychic powers.
  11. Moonstone
      Colour- Blue or sheen in a transparent to translucent body
      Composition-Orthoclase feldspar
      Hardness-6
      Specific Gravity-2.57
      Refractive Index- 1.52 -1.53
      Found in Sri Lanka, India
      Helpful in psychic work. Opens the spirit to the feminine aspect. Draws love and helps in interpersonal relationships.
  12. Turquoise
      Colour- Sky blue to green
      Composition-Cu, Al, Phosphate
      Hardness-6
      Specific Gravity-2.80
      Refractive Index- 1.61 -1.65
      Found in Iran, Mexico, Chile, Russia
      Healing stone. Attracts friendships, luck, and happiness. Releases shame and guilt.
  13. Lapis Lazuli
      Lapis Lazuli is rock made out of Lazurite , Sodalite, Hauyne Calcite, and Pyrite.
      Lazurite Sodalite and Hauyne are blue in colour. Calcite is white in colour and Pyrite is yellow in colour.
      It appears as a blue material with white and yellow patches.
      It is found in Afghanistan, Chile, Russia.
      Emotional healing and stability. High intensity stone which cleanses the spirit to bring out inner truth and peace.
  14. Garnet
      The composition of Garnet varies and it is as follows:
      Pyrope-Mg3Al2(SiO4)3
      Almandine- Fe3Al2(SiO4)3
      Spessartine-Mn3Al2(SiO4)3
      Grossular-Ca3Al2(SiO4)3
      Demontoid-Ca3Fe2(SiO4)3
      Balances your natural energy. A highly protective stone. Increases confidence and security.

Pyrope Garnet
Colour-Red
Hardness-71/2
Specific Gravity-3.8
Refractive Index- 1.72-1.76

Almandine Garnet
Colour-Purplish- Red
Hardness-71/2
Specific Gravity-4
Refractive Index- 1.76-1.83

Spessartine Garnet
Colour- Orange, Orangish-Red
Hardness- 71/4
Specific Gravity-4.2
Refractive Index- 1.80-1.82

Grossular Garnet
Variety 1- Hessonite; Yellowish –red
Variety 2- Green Grossular, Tsavorite Garnet, Green Garnet

Demontoid Garnet

Green, Yellowish-Green stones with horse-tail like Asbestos inclusions.
Lucky Birthday Gems
January-Garnet, Ruby, Hessonite Garnet- Constancy
February-Amethyst, Zircon-Success
March- Bloodstone, Aquamarine-Courage
April-Diamond, Cat’s eye-Innocence
May-Emerald, Agate-Fidelity
June-Pearl, Moonstone, Emerald-Sincerity
July- Ruby, Pearl, Green sapphire-Nobility
August- Star sapphire, Peridot-Virtue
September-Sapphire, Lapis- Prosperity
October-Opal, Moonstone, Blue Topaz- Happy Dreams
November-Topaz, Peridot, Citrine, Pearl-True Love
December-Turquiose, Zircon, Ruby-Wisdom