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Gemstone Guide

Eterniti Jewellery's gemstone guide has everything you need to know when buying birthstones and gemstone jewellery online.

The jewellery industry recognises the highest quality gemstones by the purity of their hue, depth of tone, and colour saturation. Saturation is a measure of the intensity or purity of a gem's hue and is determined by the degree to which grey or brown hues mute its defining colour. Value tends to increase with saturation, so a fully saturated purplish-blue sapphire may well be more expensive than a muted, pure blue one.

Almost all of these precious stones contain tiny fractures called inclusions. Flawless gemstones are very rare and valuable, and even most high-end ones have at least a slight amount of inclusions. Stones are rated on a scale that determines to what degree their appearance is impacted by this imperfection.


Gemstone Care


Minerals are rated and ranked according to their hardness – which is the stone's ability to resist abrasion. Regardless of which scale is used, the diamond is considered the hardest substance known to man. The most common measure of a gemstone's degree of hardness is based on the Mohs Scale - from 1 (very soft) to 10 (very hard). What the scale means is that a stone with a certain rating will scratch other minerals with the same rating, as well as any minerals of a lower hardness rating. Rubies and sapphires, which both have a rating of 9, will scratch each other – but cannot scratch diamonds, as these are rated 10.


      MOHS Rating     
                Gemstone              
           Mineral Group          
10
Diamond

9
Ruby
Corundum
9
Sapphire
Corundum
8
Topaz

7.5
EmeraldBeryl
7.5AquamarineBeryl
7.5Garnet
7AmethystQuartz
7CitrineQuartz
6.5Peridot
5.5 - 6.5Opal
5 - 6Turquoise
2.5 - 4.5Pearls


Birthstones by Month


Over thousands of years, a tradition has developed that associates certain stones with times of the year. It is likely that pagan beliefs related the time of year of a person's birth with certain characteristics. Pagan cultures are ones in which the believers tend to be in tune with nature as well as the earth's cycles and seasons – as such, different gemstones have been ascribed to different months. 


        Month         
        Birthstone      
            Colour            
         Sample         

January 

Garnet

Dark red


February

Amethyst

Purple


March

Aquamarine

Pale blue


April

Diamond

White


May

Emerald

Bright green


June

Pearl

Cream


July

Ruby 

Red


August

Peridot

Pale green


September

Sapphire

Deep blue


October

Opal

Variegated


November

Topaz

Yellow


December

Turquoise

Sky blue