Some Questions I Have On The Colored Stones

[pwsg07]

After I have learned more about the coloured stones, I have these questions.

Does an unheated colourless sapphire always show hints of colour? I have not seen too much unheated colourless sapphires. But the real colourless ones I have seen on the photo usually are heat treated

From a photo, how to tell the difference of the reflection of the camera on a gem or the extinction of the gem?

Most of the star sapphires I cannot see the stars without the help of a focus light source. Is that normal? How close should I put the light source to a stone in order to define the sharpness of a star?

I think the most difficult part is to access the tone of a stone. Some dealers claim their stone medium tone, but to me they are medium dark in tone. Is there a scientific way to determine the tone?

Thank you in advance.

 

[Bron357]

I think with most coloured gems you have to see them with your own eyes in person. Obviously vendors use special lighting and great cameras to display their wares and computer monitors don’t always accurately display colour. Even where you live and the season you are “seeing” your coloured gem affect what you see. The blue sapphire outside in sunshine is a completely different looking gem inside at night in a dimly lit restaurant!
Colourless sapphires are usually not “white clear”, most often a faint blue tone or faint yellow. I think that’s why they heat them, to increase the “whiteness”. I’m also not sure how easy it is to detect heat or no heat in a white sapphire, the inclusions are nigh impossible to see. Maybe they just assume heat if the sapphire isn’t with a lab certificate.
Star sapphires look best on a dark or vivid body tone and a light source for the rutile inclusions to “shine and shimmer” and the star to be visible. I don’t have any star sapphires but I imagine they look best in sunlight or bright light but inside at night not so great.
Sapphire, blue in this case, have three assessment criteria. There is Hue, tone and saturation. Colour is subjective as well, again that’s why I think you need to see the gem in person to make a final decision. That’s also why choosing a vendor who accepts no hassle return is important, just in case when you see it in person you decide the gem isn’t as you expected / hoped.
The darker tone and stronger saturation sapphires will always have “darker looking bits”. What they “do” is flash vivid strong blue as light hits the right facet. This is quite a different look to a weaker tone and low saturation sapphire, this will be more sparkly. Cut is more important in these type is sapphires because the lack of hue can make them “see through / windowed” if not well cut. So it depends very much on what you like to see.

 

[chrono]

1. They’re very rarely 100% clear. They will usually have some tint. Are you referring to colourless or white sapphire?

2. In time, you’ll be able to figure it out the difference between camera shadow and extinction. A video is easier to see the difference. In photos, there are background and lighting hints.

3. A star needs a single light source to show. Therefore, you must enjoy it’s body colour (and translucency) when you have diffused lighting. Note that the sun is considered a single light source, so you’ll see the star then too.

4. Nothing beats seeing the stone in person! Of course we ask many questions, see pictures and videos to lessen the risk. Again, with time, you can figure out whether their medium is the same as yours. In Asia (BKK), there’s stronger sunlight so it’ll appear more medium where they are, more medium dark in northern EU.

 

[pwsg07]

I think with most coloured gems you have to see them with your own eyes in person. Obviously vendors use special lighting and great cameras to display their wares and computer monitors don’t always accurately display colour. Even where you live and the season you are “seeing” your coloured gem affect what you see. The blue sapphire outside in sunshine is a completely different looking gem inside at night in a dimly lit restaurant!
Colourless sapphires are usually not “white clear”, most often a faint blue tone or faint yellow. I think that’s why they heat them, to increase the “whiteness”. I’m also not sure how easy it is to detect heat or no heat in a white sapphire, the inclusions are nigh impossible to see. Maybe they just assume heat if the sapphire isn’t with a lab certificate.
Star sapphires look best on a dark or vivid body tone and a light source for the rutile inclusions to “shine and shimmer” and the star to be visible. I don’t have any star sapphires but I imagine they look best in sunlight or bright light but inside at night not so great.
Sapphire, blue in this case, have three assessment criteria. There is Hue, tone and saturation. Colour is subjective as well, again that’s why I think you need to see the gem in person to make a final decision. That’s also why choosing a vendor who accepts no hassle return is important, just in case when you see it in person you decide the gem isn’t as you expected / hoped.
The darker tone and stronger saturation sapphires will always have “darker looking bits”. What they “do” is flash vivid strong blue as light hits the right facet. This is quite a different look to a weaker tone and low saturation sapphire, this will be more sparkly. Cut is more important in these type is sapphires because the lack of hue can make them “see through / windowed” if not well cut. So it depends very much on what you like to see.

Thank you Bron357

 

[pwsg07]

1. They’re very rarely 100% clear. They will usually have some tint. Are you referring to colourless or white sapphire?

2. In time, you’ll be able to figure it out the difference between camera shadow and extinction. A video is easier to see the difference. In photos, there are background and lighting hints.

3. A star needs a single light source to show. Therefore, you must enjoy it’s body colour (and translucency) when you have diffused lighting. Note that the sun is considered a single light source, so you’ll see the star then too.

4. Nothing beats seeing the stone in person! Of course we ask many questions, see pictures and videos to lessen the risk. Again, with time, you can figure out whether their medium is the same as yours. In Asia (BKK), there’s stronger sunlight so it’ll appear more medium where they are, more medium dark in northern EU.

Thank you Chrono. I am referring to the colourless or white sapphire.

 

[chrono]

There are few white sapphires to begin with. Of those few, most tend to not be attractive, displaying some brown or ruddy colouration, thus they are very often to remove this tint.

 

[pwsg07]

After looking at the blue sapphire chart, I like the vivid very light blue and the vivid light blue the most

 

[pwsg07]

Is the colour of the first sapphire in the video royal blue or peacock blue?

https://www.facebook.com/video.php?v=681694172262076

 

[voce]

20ct Burmese oval? I'd call that royal.

 

[Bron357]

Same colourless sapphire same iPhone (not exactly high tech here) but different lighting conditions makes it look quite different.
To my eyes under led light (with diamonds) it has just the very faintest blue tinge. Under bright white light, it seems very white.

 

[Bron357]

Same colourless sapphire same iPhone (not exactly high tech here) but different lighting conditions makes it look quite different.
To my eyes under led light (with diamonds) it has just the very faintest blue tinge. Under bright white light, it seems very white.

 

[pwsg07]

Same colourless sapphire same iPhone (not exactly high tech here) but different lighting conditions makes it look quite different.
To my eyes under led light (with diamonds) it has just the very faintest blue tinge. Under bright white light, it seems very white.

Thanks for the demonstration. I have seen some white/ colourless sapphires in Tucson. They are truly colourless. However, I didn't observe them under the white background. One is from Montana; another is from Sri Lanka.

 

[pwsg07]

Are the AAA and AA referring to clarity? How do I use the grading?

 

[chrono]

All I know is that AAA is better overall than AA. Other than that, you’ll have to ask the vendor because this is an non-standardized internal grading that varies from store to store.

 

[pwsg07]

All I know is that AAA is better overall than AA. Other than that, you’ll have to ask the vendor because this is an non-standardized internal grading that varies from store to store.

That why it makes me confused. Some vendors have 5As. I cannot find this A grade system information online.

 

[chrono]

Because there’s none. Each store sets their own requirements for what AA, AAA, etc means. It’s useful for buying melees but less so for larger stones.