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The first and foremost factor that inspires people to buy colored gemstones is their physical appearance. A particular stone is considered valuable if it has a beautiful color, brilliance, and transparency. However, all that shines is not necessarily valuable.
Especially when it comes to rubies, one of the most precious gemstones, it is essential to distinguish between high-quality stones and low-quality ones. Gemstone grading helps you determine the value and quality of a stone. Here are some of these factors that will help you buy high quality ruby.
Read More: How to Choose a Quality Ruby?
The quality of ruby aka Manik stone is governed by 4C’s (color, clarity, cut, and carat weight). Let's have a look at them one by one:
Read More: Understanding The 4 C's of Ruby Gemstone
Color Grading: The word ruby is derived from the Latin word “ruber” which means red. It belongs to the corundum mineral family of which sapphires are also a member. But rubies are not termed red sapphire. However, most orange sapphire are treated and enhanced to give a reddish-orange color.
The color gem grading code refers to hue, tone, and saturation.
Hue: The basic hues as per GIA in a gemstone are red(R), orange(O), green(G), yellow(Y), blue(B), violet (V), and purple (P). Hue combines both dominant and additional colors in a stone. In Manik stone red is the dominant color whereas purple is the secondary color. The true ruby color is vivid red with a purplish tint.
Also Read: Ruby vs Pink Sapphire: The Major Differences
Tone: The color gem grading code ranges on a scale of 0 to 10. The number reflects the brightness to darkness of the gem. Medium tone Manik stone is ideal. Very dark and very light rubies are considered low quality.
Learn More: What Color Ruby Is Most Valuable?
Saturation: The intensity of the color is referred to as saturation. Low quality Manik stone shows traces of brown or gray. This area is called extinction. To avoid this extinction, gems are given shallow cuts. As the gemstone saturation decreases they appear black or brown. High saturation increases ruby value.
Clarity: The clarity grading factor assesses 20 to 30% of the ruby worth. The point system for ruby clarity grading helps evaluate the gemstone’s quality based on number of inclusions, size, and visibility.
Rubies are generally included and thus fall under type 2 gemstones. On clarity grading system they are classified as:
IF (Internally Flawless): No visible inclusions seen even under a microscope (Highly rare Manik ratna)
VVS (Very Very Slightly Included): Minute inclusions (also rare)
SI (Slightly Included): Noticeable inclusions
I (Included): Visible inclusions are seen. Impacts the brilliance of the stone.
Also Know: Ruby Gemstone Origins - Best Sources of Rubies
Cut: This factor takes up 10% to 20% of the value in a grading system. A perfect cut is judged based on how fine the gemstone is cut, which is also referred to as “proportion”. This is assessed by table size, crown height and pavilion depth. If a gem is well proportioned it will reflect more light and sparkle more enhancing ruby worth. So the key points to consider:
When looked from the top the facets of Manik stone should be of the same size.
Extinction is common in Thai rubies. It should not be confused with the darker tone. Extinction is the black area in the gem that is cut too steeply. This makes the light not reflect and get trapped in an area making it appear black. The value of Ruby stone decreases with significant extinction. A high quality Manik should show 100% color and no extinction.
Consider factors such as polish, symmetry, and number of facets.
Cutting Grade of Rubies ranges from excellent to good on the point scale of 1-10.
Carat Weight: High carat rubies are difficult to find and hence fetch more price. 1 carat ruby stone price per carat in India starts from INR 2,000 and may extend upto INR 60,000 or more.
Learn More: How To Determine Ruby Stone Price? Complete Guide
Treatment: Ruby's grading system also depends upon the treatment. It is done to enhance the color and clarity of the stone. An original Manik ratna without any treatment and sourced from Mogok Valley of Burma is said to be premium. So if you are choosing a ruby for astrological purposes your priority should be that it should be free from any treatment or enhancement. One should then further access the 4Cs of the gemstone.
Read More Here: Different Types Of Rubies & Their Treatments
