Ottu sapphires

[eesmom]

Has anyone heard of them? I did a search on Google and it was a bit sparse in material. Would love some more info if anyone knows what it means?

 

[Bron357]

Sapphire crystals are not necessarily uniform in colour. The crystal can have “bands” of colour. From what I can ascertain it refers to the cutting style of a sapphire crystal with colour bands. The cutter places the best colour band at the base (pavilion) of the gem and let’s that colour, due to the facetting, be reflected around the gemstone. The colour is therefore seen throughout the gem when viewed looking down whereas a side on view won’t show the colour.

 

[eesmom]

Sapphire crystals are not necessarily uniform in colour. The crystal can have “bands” of colour. From what I can ascertain it refers to the cutting style of a sapphire crystal with colour bands. The cutter places the best colour band at the base (pavilion) of the gem and let’s that colour, due to the facetting, be reflected around the gemstone. The colour is therefore seen throughout the gem when viewed looking down whereas a side on view won’t show the colour.

Thank you @Bron357 ! Is it considered a pretty common thing? Or is it considered a "weak" character in the sapphire?

 

[FinewaterGems]

"Ottu" sapphires are a type of translucent whitish sapphires ("gueda") with spots or bands of blue. Gueda sapphires were originally considered worthless until Thai gem heaters found out how to heat them in a furnace to make them transparent and uniformly blue. The word "ottu" means "bet" in Sinhalese, so essentially the buyer was making a bet that an Ottu stone would heat to a nice transparent blue sapphire.

 

[eesmom]

"Ottu" sapphires are a type of translucent whitish sapphires ("gueda") with spots or bands of blue. Gueda sapphires were originally considered worthless until Thai gem heaters found out how to heat them in a furnace to make them transparent and uniformly blue. The word "ottu" means "bet" in Sinhalese, so essentially the buyer was making a bet that an Ottu stone would heat to a nice transparent blue sapphire.

So, does that mean an ottu sapphire must be heat treated in order to be used as a gemstone?

 

[FinewaterGems]

Not necessarily. They can be cut and sold as unheated, but are considered a "cheap" stone and are worth less than more-evenly colored sapphires. Most top dealers in Sri Lanka do not deal with them.

 

[eesmom]

Not necessarily. They can be cut and sold as unheated, but are considered a "cheap" stone and are worth less than more-evenly colored sapphires. Most top dealers in Sri Lanka do not deal with them.

How would one be able to tell if a sapphire is an “ottu” sapphire? Is there a way for someone like myself (untrained) to look at a potential sapphire and know that is it an ottu?

 

[FinewaterGems]

Viewed face up they can appear evenly colored, but if you look closely from the side of the stone you will most often see that much of the stone is colorless but with just a spot of color in the culet. There is also a "milky" or translucent appearance in many of these.

 

[AV_]

The reflecting color is delightful, worth seeing methinks.

I assume that this is a speculative offer - www, not hommage to ink in water.

 

[eesmom]

There is a stone that is local to me that my husband is seeing today in person. The seller said the word, "ottu"when he was describing and it threw me for a loop since I had never heard of that or seen it in any of the threads here!
I am so thankful that there are people here on this forum that can give me some responses regarding what I may be dealing with. Very appreciative to all that replied!