Russian alexandrite

[Marlow]

This is my russian Alexandrite - small and an gemological interesting stone. 0,22ct and good clarity.
The change is strong from medium grayish bluegreen to grayish pink BUT....

There is a deep brown colored area so the stone is bicolor and partly brownish colored. I will send these pics to Dr. Schmetzer.

Daylight


in water - daylight view parallel C-axis


in water - daylight view parallel C-axis through the table


in water - daylight view parallel A-axis


Maybe a twin zone, maybe a deeper colored area - we will see...

 

[pregcurious]

Thanks Marlow

 

[LoversKites]

That's really cool. Curious to know what the brown patch is. I'm guessing its inside the stone, right?

 

[Marlow]

Yes, it is inside - not a mineral - maybe part of one crystal of a trilling with a higher iron content ??

It is unusual in alexandrite that the c-axis ( here is the weakest color and color change.) run through the table facet to the pavillion.

 

[Marlow]

Incandescent Light

 

[chrono]

That's really cool. Curious to know what the brown patch is. I'm guessing its inside the stone, right?

That's what I thought of initially too but I know Marlow understands gemstones so if he says it isn't a mineral inclusions, then it is some sort of colour "stain".

 

[Marlow]

That's really cool. Curious to know what the brown patch is. I'm guessing its inside the stone, right?

That's what I thought of initially too but I know Marlow understands gemstones so if he says it isn't a mineral inclusions, then it is some sort of colour "stain".

The shape looks a bit like a growth structure - maybe iron rich - later the crystal growth with less iron and more chrome.
Not a fracture filled with something or another mineral.

 

[chrono]

Marlow,
I did not mean that it is fracture filled but some sort of naturally occurring mineral "stain" that interfered its natural crystal growth.

 

[Marlow]

Chrono,

yes - think this is a possible answer...I no you didn't mean that there is a fracture.

The stone has a strong red fluor with a "hole" where the patch is. Typical for iron rich zone.

 

[LoversKites]

I know iron = brown so that makes sense to me.
Why did you take the photos in water by the way?
Very interesting little gem.

 

[Marlow]

I know iron = brown so that makes sense to me.
Why did you take the photos in water by the way?
Very interesting little gem.

In Chrysoberyl Iron is responsible for yellow - brown.

I took the pic in water to reduce or eliminate reflections - so we can see the colored zone sharp.

If you have deep blue sapphires try it with the lid of a gem box. Two other boxes and the lid - build a little bridge. Some water and put the sapphire in - sure you see some zoning.

 

[Acinom]

Wow, thanks for posting Marlow! What a neat phenomenon.

 

[LoversKites]

I know iron = brown so that makes sense to me.
Why did you take the photos in water by the way?
Very interesting little gem.

In Chrysoberyl Iron is responsible for yellow - brown.

I took the pic in water to reduce or eliminate reflections - so we can see the colored zone sharp.

If you have deep blue sapphires try it with the lid of a gem box. Two other boxes and the lid - build a little bridge. Some water and put the sapphire in - sure you see some zoning.

It seems like iron is often the reason for brown colours in gems.

I don't own any sapphires otherwise I'd try your little technique.

 

[irinaalexandrovna]

A beautiful example of a rare Russian Alexandrite: https://www.1stdibs.com/jewelry/rin...ond-gold-art-nouveau-flower-ring/id-j_358642/

 

[Marlow]

Dr. Schmetzer was so kind and checked the little alexandrite ( and some little taaffeite with a big surprise - no musgravite but something else - will be a new topic)

The brown area is not iron rich - it is a mineral inclusion or better - thousands of extremely small dust like rutile particle - to small for his microscope. I will discuss it if I meet him the next time...

 

[chrono]

Marlow,
Don't leave us waiting too long. My interest is certainly perked as to what you've discovered.

 

[LoversKites]

Dr. Schmetzer was so kind and checked the little alexandrite ( and some little taaffeite with a big surprise - no musgravite but something else - will be a new topic)

The brown area is not iron rich - it is a mineral inclusion or better - thousands of extremely small dust like rutile particle - to small for his microscope. I will discuss it if I meet him the next time...

That's interesting. I only realised now that the area is quite a defined shape. I wonder why it turned out so geometric.

 

[Marlow]

I will ask him when I meet him - agree that the shape is geometric.