Highly Popular Gemstone Treatments & Enhancements

Only 1 percent of the naturally obtained gemstones are perfect and meet the textbook definition of “being flawless”. When it comes to turn the gemstones into acceptable items for the market, they have to undergo numerous processes ranging from cutting to polishing to dyeing and heat treatment. While some treatments involve only removal of the flawed parts, others include enhancements, doping and filling.

Here are highly popular gemstones treatments and enhancement processes done on diamonds, rubies, sapphires, garnets and almost every other rock known to mankind holding significant economic value.

Heat treatment:

Done incontrolled conditions, heat treatment of gemstone causes a drastic change in the colour. Rubies grow fiery red when exposed to heat. The untreated rubies and sapphires have gas bubbles and silk rutile inside them, which disappear after heating. In sapphires, heating in a flux of beryllium produces an electrifying blue shade.

Gemstones that are given heat treatment to improve clarity and brightness are:

 Blue Topaz Gemstone Beads


Done for natural emeralds, oiling is done to improve the clarity. Use of cedar oil is a universal process. Apart from clearing the surface of emeralds, cedar oil acts as a wonderful filler. The fracture filling done using cedar oil enhances the refractive index of emerald. Oiling is a temporary enhancement process owing to chances of leaching. An oiled emerald requires repeated treatment to look its best.
Oiling done using fillers and resins apply to alexandrite, rubies and chrysoberyl.


Also called gamma-ray bombardment, this is a technologically advanced process that transforms the crystalline structure of the gemstone. Largely irreversible, irradiation of blue topaz is a symbolic example of what an irradiated gemstone looks like.

Quartz minerals are irradiated with Cobalt-60 to produce brilliant amethyst in versatile colours. Colourless beryl gemstones turn into brilliant golden hued beryls, also called helidor. A colourless beryl will fetch $100 per carat, but an irradiated gemstone from beryl family will fetch anywhere between $300 and $450 in the market.

Other popular gemstones treated with gamma radiations are:

  • Tourmaline
  • Diamonds
  • Pearls
  • Zircon
  • Fluorite

 Gamma irradiation is often followed by annealing to arrive at a consistent clarity and superior brilliance.

Aquamarine Beads

Colouring and Dyein:

There are many ways gemstones can be coloured. They are either stained, bleached or dyed with colouring agents. Dyeing is probably the oldest known colour enhancement process dating back to the days of Pharaohs. Stones are either soaked in dyes or heated in a colour agent to enhance the colour.

Staining, on the other hand, is done using a penetrative solution that enters the fault lines and cracks. Commonly, black onyx and pearls are coloured by staining and dyeing process.

Bleaching is a process where the colour is removed, and not added. It adds clarity and lustre to the white gemstones. Onyx, pearls and corals are bleached to gain uniform consistency.

Depending on the extent of processing and treatment, the cost of the gemstones may vary considerably.

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