Do color change gems need to have chromium? (Not color shifters)

[Garry H (Cut Nut)]

We have debated and decided (with my store gemmo's) that color shift gems only change about one hue in different light.
Color change on the other hand all seem to have just enough chromium - at least all we have seen lightup pink reddish in very long way UV.

 

[JackTrick]

IIRC, vanadium can also cause color change. Naturally, it often accompanies chromium, but I believe vanadium tends to be the dominant source of color change in cc garnets and color change lab sapphire.

 

[Garry H (Cut Nut)]

IIRC, vanadium can also cause color change. Naturally, it often accompanies chromium, but I believe vanadium tends to be the dominant source of color change in cc garnets and color change lab sapphire.

Thanks, I guess that makes sense, I think they have some similar chemical properties.

 

[Nick_G]

I've seen pics of sapphires from Mogok and the Umba Valley in Tanzania that change from a green to a reddish colour, very similar to alexandrite. This is due to vanadium.

 

[Garry H (Cut Nut)]

I've seen pics of sapphires from Mogok and the Umba Valley in Tanzania that change from a green to a reddish colour, very similar to alexandrite. This is due to vanadium.

Sold an Umba last week and that's what prompted the question. It fluoresces pale red in very long wave UV. 405nm
So vanadium also causes fluorescence?

 

[Nick_G]

Sold an Umba last week and that's what prompted the question. It fluoresces pale red in very long wave UV. 405nm
So vanadium also causes fluorescence?

I'm not sure if it does, but it could have traces of chromium in there as well. My recent purchase of tsavorites fluoresce a peachy colour, and I wonder if there's a yellow component from the vanadium, adding to the pink/red from chromium?

Rare-earth elements can also produce colour shift effects too, e.g. bastnäsite which is cerium carbonate with fluorine and shifts colour in different lights.

 

[Garry H (Cut Nut)]

I'm not sure if it does, but it could have traces of chromium in there as well. My recent purchase of tsavorites fluoresce a peachy colour, and I wonder if there's a yellow component from the vanadium, adding to the pink/red from chromium?

Rare-earth elements can also produce colour shift effects too, e.g. bastnäsite which is cerium carbonate with fluorine and shifts colour in different lights.

My Umba is change not shift Nick

 

[JackTrick]

Sold an Umba last week and that's what prompted the question. It fluoresces pale red in very long wave UV. 405nm
So vanadium also causes fluorescence?

To clarify, are you saying that fluorescence is what had you label it as color change? Or it was a color change sapphire that also fluoresced?

 

[Garry H (Cut Nut)]

My definition of color shift is around one hue change based on illumination warm cool light source .
Color change is induced by various elements (rare earths etc) and often occurs across the spectrum. e.g. Alexandrite and Umba sapphires go green to pinkish red. skipping orange and yellow!

 

[Autumn in New England]

This is such an interesting conversation. I have nothing intelligent to add, so I'm just enjoying the free seminar.

 

[Double E]

I am pretty interested in that colour changing umba sapphire. I guess more price friendly than alex??

 

[Garry H (Cut Nut)]

I am pretty interested in that colour changing umba sapphire. I guess more price friendly than alex??

18ct and hard to compare

 

[Nosean]

Two gemstones with a reverse alexandrite color change are

Tourmaline from Mozambique - unheated with bluepurple in daylight and green in incandescent light. Copper and Manganese.

Reverse Alexanderite Color Change Gemstone, Cuprian Tourmaline from Mozambique, Laurellite

Reverse Alexanderite Color Change Gemstone, Cuprian Tourmaline from Mozambique, Laurellite -

brucefrytourmaline.com

Zircon from Mogok (Myanmar) - heated with HREE. Again purple in daylight and green in incandescent light.

Colour-Changing Zircon - SSEF

by Dr. M.S. Krzemnicki, first published in Facette 20 (January 2013) After studying and describing colour-changing bastnäsite in the 2012 Facette (Herzog 2011 & Herzog 2012), we have this year focussed research on colour-changing zircon from Burma in collaboration with Mr. O. Waldis, who kindly...

www.ssef.ch

Marlow on Instagram: "Incandescent light... #collectorgems #zircon #alexandrite #gemology #raregems #colorchangegems #colorchangezircon"

53 likes, 4 comments - marlowgems0711April 21, 2018 on : "Incandescent light... #collectorgems #zircon #alexandrite #gemology #raregems #colorchangegems #colorchangezircon"

www.instagram.com

Marlow on Instagram: "Zircon with reverse color change next to an alexandrite. Daylight color. REE are responsible for this CC. #alexandrite #raregems #zircon #gemology #colorchangegems #collectorgems"

24 likes, 0 comments - marlowgems0711April 21, 2018 on : "Zircon with reverse color change next to an alexandrite. Daylight color. REE are responsible for this CC. #alexandrite #raregems #zircon..."

www.instagram.com

The tourmalines are extremely rare - never seen one live.

The RCC Zircon are rare and quite expensive compared the other Zircon varieties.

 

[Nosean]

Sapphires from Madagascar (blueviolet to pink) and Tanzania (alexandrite-like).

Marlow on Instagram: "Two color changing sapphires (MAD/East Africa) - both unheated #sapphire #corundum #color change #alexandrite #colorchangegarnet #pricescope #gemology #collectorsgems #raregems"

30 likes, 0 comments - marlowgems0711April 16, 2020 on : "Two color changing sapphires (MAD/East Africa) - both unheated #sapphire #corundum #color change #alexandrite #colorchangegarnet #pricesc..."

www.instagram.com

 

[Garry H (Cut Nut)]

Two gemstones with a reverse alexandrite color change are

Tourmaline from Mozambique - unheated with bluepurple in daylight and green in incandescent light. Copper and Manganese.

Reverse Alexanderite Color Change Gemstone, Cuprian Tourmaline from Mozambique, Laurellite

Reverse Alexanderite Color Change Gemstone, Cuprian Tourmaline from Mozambique, Laurellite -

brucefrytourmaline.com

Zircon from Mogok (Myanmar) - heated with HREE. Again purple in daylight and green in incandescent light.

Colour-Changing Zircon - SSEF

by Dr. M.S. Krzemnicki, first published in Facette 20 (January 2013) After studying and describing colour-changing bastnäsite in the 2012 Facette (Herzog 2011 & Herzog 2012), we have this year focussed research on colour-changing zircon from Burma in collaboration with Mr. O. Waldis, who kindly...

www.ssef.ch

Marlow on Instagram: "Incandescent light... #collectorgems #zircon #alexandrite #gemology #raregems #colorchangegems #colorchangezircon"

53 likes, 4 comments - marlowgems0711April 21, 2018 on : "Incandescent light... #collectorgems #zircon #alexandrite #gemology #raregems #colorchangegems #colorchangezircon"

www.instagram.com

Marlow on Instagram: "Zircon with reverse color change next to an alexandrite. Daylight color. REE are responsible for this CC. #alexandrite #raregems #zircon #gemology #colorchangegems #collectorgems"

24 likes, 0 comments - marlowgems0711April 21, 2018 on : "Zircon with reverse color change next to an alexandrite. Daylight color. REE are responsible for this CC. #alexandrite #raregems #zircon..."

www.instagram.com

The tourmalines are extremely rare - never seen one live.

The RCC Zircon are rare and quite expensive compared the other Zircon varieties.

All these except the ziron would be color shift stones with no hanky panky from trace elements.
The last one - zircon on the right - changes same as alexandrite, greenish in cool and pinkish in warm light. No reversal there. Bit it is a color change.

 

[Nosean]

Alexandrite is green in daylight - the RCC Zircon and the tourmaline is green in incandescent light. It is an reverse color change.

 

[Garry H (Cut Nut)]

Alexandrite is green in daylight - the RCC Zircon and the tourmaline is green in incandescent light. It is an reverse color change.

We must be looking at different stones or videos?

 

[Garry H (Cut Nut)]

The stone on the left does a slight predictable color shift from green to blue. The stone on the right does a color change from pinkish to greenish.

 

[Nosean]

Zircon with Unusual Color-Change Behavior

Different types of illumination produce marked variation in color in a cushion-cut zircon.

www.gia.edu

 

[Garry H (Cut Nut)]

Zircon with Unusual Color-Change Behavior

Different types of illumination produce marked variation in color in a cushion-cut zircon.

www.gia.edu

That is a color shift from teal greenish blue to blueish green (no purple there as can be seen in the paint eyedropper)



The green stone is closer to blue than it is to green.
So this stone is a color shift, not a color change Nosean.

 

[Nosean]

Maybe you contact Dr. Palke (GIA) for further informations.

 

[Garry H (Cut Nut)]

Maybe you contact Dr. Palke (GIA) for further informations.

I am sure they are monitoring us.
But in my experience GIA rarely quote me and certainly spent millions on patent wars with me.