Welcome to the ruby hub. This page is your gateway to a lot of information you’ll find useful when working with rubies.

Who is this page for?

This page is useful for anyone working with rubies. If you are a jeweller, then there is practical information such as hardness, weights by size and other useful facts. If you are a jewellery designer, you might find the sections on colour, origin and availability more interesting. You might work as a salesperson in a shop and are involved with the selling of jewellery with rubies in. You might find origin, treatments and certificates more useful. If you just love looking at rubies and want to further your general knowledge on the subject, you’ll enjoy the whole thing.

This is not a gemology course. It is an overview, to give you some practical information you might need while working with, or looking at rubies. If you want more information, you can either contact us directly, or look at some of the links below relating to ruby knowledge.

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Please bookmark this page, as we will be adding resources and links to it on a regular basis.

You might find it useful to download this guide, or pages from it, to keep offline to refer to.

Please click this link to get your free copy.

As gemstone suppliers based in London, Geneva and Tel Aviv, we feel it is essential to give you all the knowledge you need to work with rubies more confidently. All the gemstones you see on this website belong to Haruni Fine Gems and are backed by a money back guarantee and free shipping worldwide.

If you would like any more information on the gems on this website, just contact us via the form on the gem page itself, chat, email, or call us at the number at the top of the page.

Pages connecting to the HUB

Below are essential snippets of information relating to rubies. Click the header of each section to read more into each topic.

Ruby Sizes and Weights

All You Need to Know about Rubies

Looking After Your Ruby





Often referred to as the king of gems, Rubies radiate warmth and vitality and when worn represents love, health and wisdom. Ruby, the July Birthstone, has been a very popular gemstone since antiquity, and is one of the most historically significant coloured gemstones. The ruby has now entered a new era of popularity with many people opting for this romantic stone as an alternative to diamonds in their wedding jewellery.

Due to their symbolism of strength and vitality, rubies are also a popular gemstone to wear for men.



The origin of a gemstone can greatly affect its value. It is more important in rubies, sapphires and emeralds than in fancy colour diamonds, with the exception of pink Argyle diamonds.

Rubies have traditionally been mined in Southeast Asia, especially Thailand, Burma, and Cambodia, but more recently in central and eastern Africa, in Tanzania and Mozambique. Today however new sources are coming online such as Greenland, which has the potential to be a source of commercial rubies.


Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness. Amongst the natural gems only moissanite and diamond are harder, with diamond having a Mohs hardness of 10.0 and moissanite falling somewhere in between corundum and diamond.


Heating rubies to improve colour is very common, accepted and has been done for centuries. It is mainly used to improve the colour and purity of gems. The most common treatments are “Heat Treatment”, “Glass Filling”, “Clarity Enhancement” or “Beryllium treatment”.

Just to give you an idea, about 1% of all rubies extracted from the ground are not treated in any way. They go through some process that in some way improve the way they look. Heating is the most acceptable, but whatever the treatment, it is essential that it is disclosed on presentation of a gem. You will see that on our website, all gem  treatments are listed with every stone.


Rubies, on the whole, are very durable stones and are safe to use in jewellery dips and ultra-sonic cleaners. However, avoid using strong direct heat with untreated stones as this could not only affect the colour, future recertification and also VALUE.


Ruby comes in red and bright red as well as red with secondary hues of pink, orange, violet and brown. Pure red, pigeons blood and red rubies with a purplish secondary hue are the most desirable ones. Flawless rubies are extremely rare. Small amounts of typical rutile inclusions aren’t bad and in fact can improve the colour of the stone by breaking up and scattering the light throughout it.



One of the most useful tools a jeweller can have at their disposal is an understanding of how much gemstones of a certain size weigh. In the chart below, we give an overview of what different shape ruby gemstones weigh according to their size.

Oval-"mm" 4x3 5x3 5x4 6x4 7x5 8x6
Ruby 0.24 0.31 0.5 0.6 1 1.6
Round-"mm" 2 2.5 3 3.5 4 5
Ruby 0.05 0.09 0.14 0.22 0.38 0.65
Octagon-"mm" 5x3 6x4 7x5 8x6 9x7 10x8
Ruby 0.45 0.75 1.2 1.75 2.9 4
Pear-"mm" 5x3 6x4 7x5 8x5 9x6 10x7
Ruby 0.3 0.5 0.85 1.1 1.8 2.5
Marquise-"mm" 4x2 5x2.5 6x3 7x3.5 8x4 10x5
Ruby 0.09 0.2 0.32 0.44 0.75 1.2


While Cut, Clarity, Colour and Carat weight are important when grading gemstones, value is most heavily weighted against its colour, as opposed to white diamonds, where the cut proportions and clarity are other primary indications of value. As a general rule, the more intense the colour, the rarer and more valuable is the stone.

With sapphires and emeralds, as with rubies, the principles are the same, but not so easily quantifiable.





Colour is always going to be top of the list when grading gemstones, as with diamonds. With colored stones, the uniformity, beauty and quality of the colour is a primary determinant of quality and value.




With colored gemstones, the intricacy of the cut does not affect the beauty and the reflection of light of the stone in the same way that it will for a ‘white’ diamond or colored diamond. Colored stones have their own natural “glow”, which is only enhanced by the quality and style of the stone’s cut.

A simple cut can showcase the high points of a colored stone just as well as a complex cut. Unlike diamonds, a higher number of facets will not influence the values of the stone. In fact sometimes it may detract from the potential beauty of the stone.




Clarity refers to the stone’s lack of inclusions. It is worth noting that inclusions in colored stones are exceptionally common and only influence the price of a stone to a degree.

Unless the stone is eye clean, or loupe clean, which can fetch a much higher price, conversely opaque stones will be a lot cheaper.




All gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as as paperclip.

Just as a dollar is divided into 100 pennies, a carat is divided into 100 points. Because even a fraction of a carat can make a considerable difference in cost, precision is crucial and highly specialised weighing machines, known as a Balance, is used for this purpose.


Generally speaking, most gemstones undergo some treatment process. I would go so far as to say that it is normal for rubies, sapphires and emeralds to have undergone some treatment or another and is quite acceptable, providing it is disclosed.

Whether you have a natural unheated ruby, or treated one, or it’s synthetic for that matter, all information pertinent to any enhancement process done to a natural gemstone must be disclosed when:

  1. the stone has undergone any treatment process; or
  2. the treatment is not permanent and its effects are lost over time (e.g. oil in emeralds); or
  3. the treatment creates special care requirements for the gemstone to retain the benefit of the treatment (e.g. oil in emeralds); or
  4. the treatment has a significant effect on the value of the gemstone (e.g. heat treatment in rubies and sapphires, or oil, or resin in emeralds, or irradiation in diamonds).

Why is this so important? Principally to tell you if stones have undergone any treatments that may affect their value. As the gemstone and diamond business has become more accessible, it has also become the target of fraudsters and criminals, looking to cheat buyers out of their hard earned money. There are websites and Facebook groups
dedicated to these scams and the stories are endless. Fraud affects both the end consumer and those inside the trade. So it is reasonable for consumers to demand full gemstone descriptions including certificates and lab verification of value points on stones, especially for larger or more expensive pieces. Thus, familiarity with the major
laboratories and certificates issued has never been more relevant.



As mentioned above, Rubies come from a number of sources around the world. The origin of a ruby is one of the most important factors when determining price, all other factors being equal. However, you would also need to consider the market you are selling in to see how the combination of factors comes into play.

By far and away the most highly sought after and ‘expensive’ rubies come from Burma/Myanmar and in particular the Mogok area. Clean stones, of ‘pigeon’s blood’ colour, that have no treatments applied to them, outstrip any and all other gemstones including diamonds (perhaps with the exception of natural pink, red, blue and green diamonds). Below 5 carats stones are in the tens of thousands of dollars, above 5 are in the hundreds of thousands.


Today Mozambique, spearheaded by the production of rubies by Gemfields, offer a consistent and reliable source of rubies, although fine unheated stones from here also command strong prices.


Depending on the market you are selling in, may determine where you find stronger demand. For example, in the USA a heated Burma ruby may be more desirable than an unheated Mozambique ruby and as a result, may fetch a similar price.


When working with coloured gemstones and diamonds, today more than ever, it is important to be able to have the stones independently evaluated. It is for this reason the gemstone laboratories have become vital players in the gemstone industry.

When working with coloured gemstones and diamonds, today more than ever, it is important to be able to have the stones independently evaluated. It is for this reason the gemstone laboratories have become vital players in the gemstone industry.

The main labs to consider here are GRS certificates, by far the biggest and most commercial; Gubelin, essential for very high value stones; SSEF, good for emeralds; AGL and GIA essential for the United States. There are lots more local laboratories, that can generally tell you whether a stone is treated or not and might have an opinion on the origin of a gemstone, but any stone over a certain value will need to be accompanied by one or more of the labs listed above.

Whilst cut is secondary in a gemstone, the purpose of a Gemstone report is to tell you a) where the stone is from, b) what treatment it has undergone, and c) offer a colour description. There are now a few colour descriptions for coloured stones that will enhance the value of a stone dramatically. They are ‘Pigeon’s Blood’ and ‘Vivid Red’ for certificated rubies, and ‘Vivid Royal Blue’ and to some extent ‘Cornflower Blue’ for sapphires. For Emeralds, it’s the presence of oils, or lack of, that will have a big influence on price, especially for Colombian stones.






Get The Look: Ruby Red

Most Expensive Rubies

July Birthstone

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