What makes some rubies a pure red?

[Indylady]

Hi Friends!

What makes some rubies a pure red that never shifts?

I have been a ruby fan for years and years. I have several Burmese that are a gorgeous red pink with flouro, and had (have lost it since) a very lovely deep red Tanzanian ruby from Barry without flouro. I used to think those pink-red Burmese were the top of the top. Recently, I acquired an absolutely fabulous red-only ruby. I’ve never seen such a ruby. It never shifts to purple, pink, or orange. The ring on my middle finger is one of my old little Burmese rubies, and the ring on my ring finger is the new one. It looks a little dark in the photo, but it doesn’t look dark at all IRL. It doesn’t seem to have flouro. It’s gorgeous and I’m stunned. The vendor is definitely reputable. What makes this little ruby different? Is there a chance it’s a spinel?

 

[chrono]

A pure red spinel that does not shift is also a needle in the haystack. Chromium is responsible for the red colour in ruby and spinel. The more chromium it has, the redder it is.

 

[autumngems]

Hi Friends!

What makes some rubies a pure red that never shifts?

I have been a ruby fan for years and years. I have several Burmese that are a gorgeous red pink with flouro, and had (have lost it since) a very lovely deep red Tanzanian ruby from Barry without flouro. I used to think those pink-red Burmese were the top of the top. Recently, I acquired an absolutely fabulous red-only ruby. I’ve never seen such a ruby. It never shifts to purple, pink, or orange. The ring on my middle finger is one of my old little Burmese rubies, and the ring on my ring finger is the new one. It looks a little dark in the photo, but it doesn’t look dark at all IRL. It doesn’t seem to have flouro. It’s gorgeous and I’m stunned. The vendor is definitely reputable. What makes this little ruby different? Is there a chance it’s a spinel?

Beautiful color, who is the vendor if you don't mind me asking?

 

[Bron357]

Rubies are pleochroic. They show a slightly different colour depending on the axis viewed.
one axis is a pinker red the other a more orange red.
the pinker red is the “preferred” axis.
That’s one job the cutter has to get right to realise the “best colour” face up. Sometimes the crystal has inclusions or a shape that doesn’t lend it to cutting it one axis.
Spinel is not pleochroic.

 

[Autumn in New England]

What @chrono said. Such a beautiful ring! Congrats!!

 

[E H]

According to my limited knowledge, ruby is a hard stone. Too much chromium (Cr) will turn the stone toward pink. A slight iron (Fe) will turn the stone more red. However too much iron will turn it to a garnet like ruby.

So a perfect ruby is the one that have high chromium, but just enough iron to make it look red. Only then the ruby will be red without missing the fluo/glow

I hope a gemologist can confirm this.

 

[Autumn in New England]

According to my limited knowledge, ruby is a hard stone. Too much chromium (Cr) will turn the stone toward pink. A slight iron (Fe) will turn the stone more red. However too much iron will turn it to a garnet like ruby.

So a perfect ruby is the one that have high chromium, but just enough iron to make it look red. Only then the ruby will be red without missing the fluo/glow

I hope a gemologist can confirm this.

I think you're spot on. I recall reading once that Asian miners have a saying that the best Burmese rubies look Thai, and the best Thai rubies look Burmese. What they mean is that Burmese rubies often veer too pink, because they possess very, very little iron as they grow within marble host rock. Thai rubies have a purer red color thanks to a higher amount of iron, but the iron also quenches fluorescence (Thai material often lacks silk inclusions as well). I love Mozambique rubies because they often straddle the iron content line quite well = pure red, strong fluorescence, and silk.

 

[kenny]

What makes some rubies a pure red?​

Pigeon blood.

 

[E H]

I think you're spot on. I recall reading once that Asian miners have a saying that the best Burmese rubies look Thai, and the best Thai rubies look Burmese. What they mean is that Burmese rubies often veer too pink, because they possess very, very little iron as they grow within marble host rock. Thai rubies have a purer red color thanks to a higher amount of iron, but the iron also quenches fluorescence (Thai material often lacks silk inclusions as well). I love Mozambique rubies because they often straddle the iron content line quite well = pure red, strong fluorescence, and silk.

Actually, ive seen some tanzanian ruby that look "pure" red, strong fluo, no silk tho.

That being said, all sources are able to produce beautiful ruby. The best ive seen was a burmese from namya instead of mogok n mongshu.

 

[Autumn in New England]

Actually, ive seen some tanzanian ruby that look "pure" red, strong fluo, no silk tho.

That being said, all sources are able to produce beautiful ruby. The best ive seen was a burmese from namya instead of mogok n mongshu.

Yes, Tanzania and Vietnam both produce some fine material as well!

 

[LilAlex]

Apart from the color and chemical composition and fluorescence -- and it is admittedly hard to tell from the tiny photos -- the one on the right looks much more crystalline and much better cut so everything about it "pops" more. The smaller one looks sleepy with no light return.

 

[VividRed]

Beautiful color, who is the vendor if you don't mind me asking?

I have the same question

 

[fredflintstone]

Though a Ruby, Spinel, Rubellite might look pure red, there is always a slight modifier of orange or purple.

The AGL shows this in their color grading system percentages of the modifying color.

GIA Gem Set uses - very slightly reddish or purplish - slightly reddish or purplish - reddish or purplish - strongly reddish or purplish.

 

[Indylady]

A pure red spinel that does not shift is also a needle in the haystack. Chromium is responsible for the red colour in ruby and spinel. The more chromium it has, the redder it is.

Thanks for the thorough answer! Good to see you @chrono!

 

[Indylady]

I think you're spot on. I recall reading once that Asian miners have a saying that the best Burmese rubies look Thai, and the best Thai rubies look Burmese. What they mean is that Burmese rubies often veer too pink, because they possess very, very little iron as they grow within marble host rock. Thai rubies have a purer red color thanks to a higher amount of iron, but the iron also quenches fluorescence (Thai material often lacks silk inclusions as well). I love Mozambique rubies because they often straddle the iron content line quite well = pure red, strong fluorescence, and silk.

Love the nuance here! Thanks for the rundown, such depth of knowledge on this forum - struggling to tag you @Autumn.

 

[LilAlex]

...such depth of knowledge on this forum - struggling to tag you @Autumn.

I think the mods have to pre-approve any tagging of @Autumn in New England. She does not like to be disturbed.

 

[Autumn in New England]

I think the mods have to pre-approve any tagging of @Autumn in New England. She does not like to be disturbed.

 

[VividRed]

Though a Ruby, Spinel, Rubellite might look pure red, there is always a slight modifier of orange or purple.

The AGL shows this in their color grading system percentages of the modifying color.

GIA Gem Set uses - very slightly reddish or purplish - slightly reddish or purplish - reddish or purplish - strongly reddish or purplish.

Sadly, AGL abandoned that system several years ago. I think it was brilliant and unique, but apparently the market didn’t value it. They replaced it with the ColorCodex, which is probably better but even fewer people use it…it’s too complicated and expensive. The trade wants simplicity

 

[Indylady]

I have the same question

@Autumn in New England and @VividRed - I did not want to share, but alas, I shall - the vendor is Michael with Litnon. I’ve been buying from him from 2013 and I’ve never been unsatisfied - Michael is a swell guy and his gems are A+.

 

[VividRed]

@Autumn in New England and @VividRed - I did not want to share, but alas, I shall - the vendor is Michael with Litnon. I’ve been buying from him from 2013 and I’ve never been unsatisfied - Michael is a swell guy and his gems are A+.

Thank you for sharing. I have my eyes on some of his stones but never pulled the trigger. That ruby of yours was not on the website, was it? I don’t recall seeing it anyway, great purchase, it’s really lovely!

 

[Indylady]

@VividRed - it was on the website! I must have scooped it up quickly

 

[T L]

Just my opinion, but I have never seen a pure red ruby or spinel, as there is a slight pink or orange secondary color to my eye. Some people, for example, think pinkish reds are more pure red, or vice Versa with orange reds.

 

[voce]

Just my opinion, but I have never seen a pure red ruby or spinel, as there is a slight pink or orange secondary color to my eye. Some people, for example, think pinkish reds are more pure red, or vice Versa with orange reds.

Pure reds exist, eyes differ. The same stone can appear different to your eyes, and it's possible you always see a pink or orangish tint.

 

[icy_jade]

Pure reds exist but they are rarer than the ones with secondary colors