Natural Ruby Cabochon Factory 2nds

Natural ruby with no heat for $15 per carat.

Over 300 pieces of natural ruby cabochons. No heat or any treatment. These are factory 2nds and all have eye visible surface defects and inclusions.

Weights are from 0.3ct to 29ct.

I will sell these for $15 per ct, or make an offer for the whole parcel.

Ruby Cabochons Factory 2nds
Ruby Cabochons Factory 2nds

Photo taken at midday with natural light.

Medium Dark, Strong to Vivid Ruby

Ruby mined Madagascar and cut in Bangkok is showing excellent color.

These are some of the latest cabs from the Madagascar rough ruby bought last year.

Ruby Cabs Medium Dark to Dark Tone with Moderately Strong to Strong Saturation
Ruby Cabs, Medium Dark to Dark Tone with Moderately Strong to Strong Saturation
Ruby Cab variations light to dark tone
Ruby Cab variations, light to dark tone

These are straight from the mined rough, with no heat or other treatment.

How do you like your coffee?  Dark and strong, like my rubies.

We can cut to any shape/size and calibrate to 0.1mm tolerance.

Gold Sheen Sapphire and Ruby in Mens Jewelry

Gold sheen sapphire and dark, vivid ruby is ideal for men’s jewelry.

Typical design styles for men’s jewelry use flat mountings with large(er) size gemstones.  This requires a faceted gem with a larger table size, or flatter cabochon that presents well, which favors opaque over transparent stones.

For example, this gold sheen sapphire ring has a 45ct stone with a 22mm x 16mm table. The faceting picks up brass, copper and gold tones as light plays across the surface.

45ct Gold Sheen Sapphire Men's Ring
45ct Gold Sheen Sapphire Men’s Ring

The rubies in these rings are cabbed from the same piece of rough ruby. In larger sizes, the dark tone with strong saturation is great for men’s rings, yet still beautifully feminine in smaller sizes.

20ct and 10ct Mens and Womens Ruby Cabochon Rings
20ct and 10ct Men’s and Women’s Ruby Cabochon Rings

What is a Ruby?

What are the criteria that gemological institutes follow to determine if a sapphire is a ruby? Can there be pink rubies?

The process to determine a ruby is straightforward:

  1. Is it corundum? If no, not ruby, if yes then:
  2. Is it red? If yes, then ruby, if no then it is sapphire

There is no pink ruby, pink corundum is called pink sapphire. Any colour of sapphire that is not blue is generally known as fancy sapphire.

However, what is ‘red’ and when does light red become pink? Is reddish orange still red, etc is a matter of individual opinion. Both hue and tone have to be taken into account.

This is a colour hue chat:

GIA Hue Chart
Hue Chart used in GIA Color Gemstone Grading

As you can see, there is no ‘pink’. Pink is a lighter tone of red.

This is a tone chart:

Gemstone Tone Chart
Gemstone Grading Tone Chart

To make it confusing, tone is often referred to as saturation. While this chart says ‘saturation’, what it is really showing is tone:

Not a tone chart
Chart uses ‘saturation’ where it means ‘tone’

So when grading a stone as ruby rather than pink or fancy sapphire, it needs to be ‘red’ with medium or better tone. Subjectively, one grade difference is acceptable – what I might call ‘red’, you might call ‘slightly purplish red’, or what I might call ‘medium’ tone, you might call ‘medium light’, and that is ok.

But there is no absolute definition for ruby, some labs might class ruby as anything with red in it, others might say red only, or some might include orangish red and slight purplish red.

Just to be clear about ‘saturation’, the saturation scale as defined by the GIA goes from ‘brownish’ to ‘vivid’ for red gemstones. It should make no difference to the actual classification of whether a gem is ruby or not.

Confusing, right? Yes, at first. But once you get your ‘eye in’ for ruby, you can pretty much tell at a glance. A definition I like to use is that if corundum can return a red ‘flash’ (a property of ruby is it returns more red light than it receives), then it deserves to be called ruby.

This is a sample of ruby colour variation:

Ruby color variation
Ruby color variation


The best possible colour of ruby is called ‘pigeon blood’, but that is a whole other story.

Ruby Catalog

I have been working on cataloging and publishing a catalog for ruby cabs from the parcel of rough ruby we bought earlier in the year. I was thinking about using a simplified grading system that groups colour/finish/proportions into one metric called ‘appeal’, but it soon became apparent that it would not be workable.  Instead I have used the GIA grading method.  After consideration, it can’t really be simplified or improved on in any helpful way.  And no need to reinvent the wheel.

It took a couple of days to develop the framework for the spreadsheet, going through several iterations before I was happy with it.  The version I am running with will auto-generate a long form description from the grading information.  I can then just cut and paste that into the description field of the product on the website.  I was quite proud of that little bit of spreadsheet scripting, until someone expressed disappointment that it didn’t just automatically post to the website instead of having to manually cut an paste.  Alas, the skills for that type of coding left me long ago.  Nevertheless, I am pleased with the functionality of my catalog spreadsheet as it is.

Given a base price for the ruby, the spreadsheet will also generate a price. That part still needs a little bit of work, but basically it works on giving a high value to the ‘sweet spot’ of hue, tone and saturation, with modifiers for clarity, finish, proportion and treatment.  The base price I take from the average street/negotiated price I see in the market for unheated ruby cabs.

The end result looks like this:

Ruby Catalog Spreadsheet
Ruby Catalog Spreadsheet

Which gives me a price from $38 to $128 for the best colour/finish grade stones.  Market pricing for ruby cabs at the moment starts at $5 per carat for heat/glass filled, $20-$80 for heat treated and $50-$150 for natural/no heat.

The autogenerated description looks like this:

Autogenerated description from grading data
Autogenerated description from grading data

It will be easy enough to replace the commas with line breaks using a text editor if I want the formatting to look better on the product web page.

Now, I know what you are asking.  What about the rubies themselves?  They are much more interesting to look at that a spreadsheet, after all.  So here is a sample of some we have photographed so far:





The next task will be to take the spreadsheet and publish it as a catalog table on the website.  That should be straightforward, and I can include a thumbnail of each gem as well, which will link to the full size picture.  I expect to have that completed pretty soon.

In the meantime, if you would like more information on the any particular piece, or for rubies in general, just email me at


New Factory Cuttings – Ruby

I have just seen the latest cuttings from the factory for ruby.  We are getting more range of colour and gradings as we progress into the parcel.

Tray of ruby cabochons
Tray of ruby cabs sorted by colour grade
Tray of dark ruby cabochons
Tray of darker ruby cabs sorted by colour grade

I am seeing quite a lot of medium-light and slight purplish red natural unheated ruby cabs in the market now, between $200 and $300 per carat.  The lighter stones we are getting from the parcel would match that grade.

Some, like these, are at the other end of the tone scale with strong purple red to purple/red hue and strong saturation:


Dark Ruby Cabochons
Dark ruby cabs

But I have to say, I do prefer the medium/dark tone best of all:

Medium Dark to dark Ruby cabs
Medium Dark to dark Ruby cabs with moderate to strong saturation

SJW gems can supply ruby cabs in calibrated sizes to any specification.  We own the rough and control the production through to the final polish and shipment.  We can accommodate order sizes up to 10,000 carats per month, and welcome small orders from collectors and independent designers.  Talk to us now for your Christmas Season orders!

Quick Guide to Buying and Investing in Ruby

Some tips and advice for people interested in buying or investing in ruby in the longer term.  The main things to consider and avoid.

Ruby is one of the ‘big three’ of precious gemstones – Ruby, Sapphire and Emerald.  At one time these were the only types of gems considered ‘precious’, and everything else was ‘semi=precious’.  The finest ruby is worth more than diamond, but you can find ruby from as little as $5 per carat (not that you would want to buy it though).

  • Natural Ruby – For investment purposes, only ever buy natural ruby.  Manufactured ruby looks good and is fine for less expensive jewellery, but as an investment it has no long term appreciative value.
Ruby Ring
1 ct Ruby gold ring. Natural ruby with mild heat treatment.
  • Glass Filled Ruby – When buying natural ruby, absolutely stay away from glass filled ruby!  I can not stress this enough,  There is a lot of glass filled ruby around at the moment and you can usually tell because it sells for under $10 per carat.  Glass filled ruby is not a permanent treatment, and the gem will deteriorate quite quickly over time.  When it is new it is hard to spot, but after even as little as a few months the gem starts to become cloudy as stress fractures build up in the glass.
  • Heat treatment – Heat treatment of ruby and sapphire has been around for hundreds of years, and is so common that the GIA advises that unless you have certain knowledge otherwise, assume your ruby is heat treated.  When done properly it improves the clarity, colour and appeal of the gem.  However, there is some risk that ‘heat treatment’ may be used to describe a gem that has been glass filled (which is a type of heat treatment). Unless you know what to look for or are buying from someone you trust, avoiding heat treated ruby will ensure you are not getting an inferior glass filled gem. For an excellent article on heat treatment, see A Brief History of Heat: Heat treatment of ruby & sapphire by Richard W. Hughes.
  • Other Treatments – Generally all related to heat treating, other processes can include the addition of chemicals to penetrate or coat the gem and improve the colour and fill in any surface flaws.  When a coating is applied it is called ‘diffusion’, and if the coating gets scratched or damaged, the appeal of the gem will decrease. Irradiation is another surface treatment where the gem is exposed to beryllium.  This is a temporary treatment that will improve the colour, but soon wears off.   These treatments are detectable in a gemological lab and always decrease the long term value of the gem.
  • The four ‘C’s – Cut, Clarity, Colour and Carat size apply to rubies just like any other gemstone.  Large carat rubies (over 4 carats) are particularly rare.  There is an excellent guide to the frou c’c of rubies at
  • Unheated – For any given quality, unheated, natural ruby commands the highest price.  A 10x jewelers loupe is usually sufficient to tell a gem with heat treatment from an unheated one.  For investment purposes and longevity, nothing will surpass unheated natural stones.

Unheated natural ruby 1.3ct

Unheated natural ruby 1.9ct

Unheated natural ruby 2ct

Large unheated natural ruby 16.35ct
  • Types of Ruby Cuts – Rubies can be faceted or cabbed, both are beautiful.  Generally the best stone is used for faceting,while more opaque and darker stone is used for cabochons.  Hence, faceted ruby usually has a higher price per carat than cabochon.  However, ruby cabs will sometimes have a star phenomena, caused by needle like inclusions of rutile.  The more prominent the star, the better.  Like sapphire, ruby will have a six arm star, or sometimes, very rarely, a 12 arm star.
Star Ruby Earrings
Star Ruby Earrings

If you have more questions about buying or investing in ruby, email me at, I will be very happy to help you.

Investing in Gemstones

I sometimes get asked if gemstones are a good investment, and if so, how to get started.

The answer varies, depending on what the investors goals are.  For most people not in the gem industry. investment can be broken down into three categories:

  1. Short term investments
  2. Long term investments
  3. Legacy investments

Each of these has its own benefits and pitfalls, but the common requirement to be successful in each is Know What You are Doing. Either by research and study, or by getting trusted expert advice.

1.  Short Term Investment

The attraction of short term investment is to buy ‘a bargain’, currently worth much more than you paid, and then on-sell it to someone at a price closer to its market value.  There are certainly genuine bargains to be had, either through luck, in depth market knowledge, or usually a combination of both.  But for every genuine bargain there are perhaps ten deals that look like bargains, but turn out to be not so good later on.

On the whole, the vast majority of gem traders describe their products honestly.  Out of hundreds I have dealt with in Sri Lanka and Thailand over the years, I don’t think a single one has knowingly sold me something that isn’t what they said it was. But whether it was a ‘bargain’ or not, was completely up to my knowledge that, the very very good, price they offer may actually be twice the going market rate for that particular gem.  Or just what degree of heat treatment it has.  Or just what process was used to give it that particular colour.

When I first began to buy gemstones in Sri Lanka many years ago, I was very fortunate.  One thing that helped was that the country was still fighting a civil war, and apart from UN observers that rarely stepped outside their compound, there were very few westerners, and even fewer looking to buy gemstones.  I was treated very well by the traders I bought from, and was able to get some very good pieces at prices just not possible any more.

ruby ring 2ct
2 carat Ruby Ring with white sapphire. Bought 10 years ago in Sri Lanka for $500, the gemstone is now worth over $5,000
This fantastic flawless 7 carat Tanzanite was bought in 2008 from Zams in Colombo. The price of Tanzanite has fluctuated, but the price of a rare and beautiful stone like this will always appreciate.
This 4.5 carat Tsavorite is perhaps my favourite. Tsavorite is a fantastic but underrated gem – the same colour as emerald but the same refractive index as sapphire, and ten times rarer than either.

The problem for me though, is that as a short term investment, they are useless – because they are so good, I don’t want to part with them.  I would much rather keep them as a legacy asset for my children and grandchildren.

Nevertheless, it proves bargains are possible, even for the novice, but needs luck (in my case) and/or knowledge (which for me came later on).

There is another case too, and that is just to buy the gemstone for its own beauty.  Certainly, that was the basis for all my early purchases.  Because whatever I spent I thought was a worthwhile amount to get a beautiful gemstone.  In this case the monetary return is secondary to the subjective feeling of owning something really beautiful.

2. Long Term Investment

As long as the gemstone is genuinely a precious gem, then at some point in the future it will be worth more than the amount paid, whatever that amount was.  Say the market price for a particular sapphire is $1,000, but you pay $2,000.  You have lost out in the short term, but within, probably not more than, ten years,  it will reach the initial value paid, and in 20 years will be worth $4,000, after 30, $8,000, and so on.  The average 7.2% yearly appreciation in value overtakes whatever ‘mistake’ may have been made at the initial purchase.

Even for someone quite clueless, the intrinsic value of owning something rare and precious will be great enough in the long term to overcome the high price they may pay.  To give one example, 30 years ago I bought a diamond engagement ring for, what was to me then, a considerable sum of money – $2,000 – a months salary.  It was bought the most expensive way possible, from a retail jeweler who specialized in engagement rings. Now, the diamond in that ring is worth over $15,000.  So in the cold light of purely and investment, the amount I paid was not so bad.  But in addition to that, I had the pleasure for 25 years of seeing a very lovely diamond grace the hand of a beautiful woman.

g-tea-aqu-001001-6-45-new2Gold Sheen Sapphire Collectors piece Unique

Bought right, Aquamarine and Gold Sheen Sapphire are both excellent long term investments.

As long as they are the genuine article, buying gemstones with the view to keep them as a long term investment carries little risk.  Of course, if you can get a good price in the initial purchase, all the better.

3. Legacy Investment

This is the big one.  The one that is for the benefit of your kids and grand kids, to build an collection that will be a secured asset well into the future.

There are sound investment reasons to do this, but here is just one that I think is a compelling justification.  Say you use your saved cash to invest in property; the ‘buy in’ amount is going to be around $500k at least.  Yes, property will always over time increase in value, but it is not without overheads.  The land price might increase, but the building and fixtures are continually depreciating.  And then there are bad tenants, changes in zoning, and many things that can happen that you have little or no control over.

Consider gemstones on the other hand.  The overheads are minimal.  You may keep them in a safety deposit box at the bank for a trivial amount per year, or in a safe at home.  Insurance is no more than any other asset you own.  The appreciation of the asset is about the same as property, with without anywhere near the overheads and complication, and with complete control over the assets.  Instead of needing half a million dollars to start off, gemstones can be added to incrementally for only a few thousand dollars a time.  Then, should at some point you need to sell, there is the flexibility of selling in small units rather than one big chunk as you would with property.

Natural Ruby Cabochon No Heat
Natural, unheated Ruby is a fine way to start a long term or legacy investment in gemstones.


Whatever the investment type may be, I can’t stress enough how important it is to research yourself or get expert advice from someone you can trust.  The longer the term you plan to invest, the less risk there is, but it is still better to get off to the best possible start.


About my company, SJW Gems: My goal with SJW Gems is to give you the best, most beautiful gemstones I can find, tested in my own lab, at a price far below anything you would expect to pay elsewhere. I try to adhere to my personal motto of ‘twice the size at half the price’.

I only buy stones that I like, and would like to have in my personal collection. So, I am happy to offer my personal guarantee that if you are ever dissatisfied with your purchase from me, for whatever reason, I will buy the stone back from you at the same price you paid.

You can read the history and more information here –