ID help: Yellow Sapphire or Yellow Topaz??

[MTswirls]

Hi everyone,

I'm trying to determine if these yellow gemstones are sapphires or topaz. I don't know if there is any way to be certain from photos, but I'd still really appreciate any opinions. The ring is set in 18K white gold with diamonds. The yellow stones have a hardness of 8 (when I set my diamond tester at level 4 based on the size of the stones) which has led me to believe they are either sapphires or topaz. Thanks so much to anyone who can help!

 

[Bron357]

The big problem with using any gem tester (I have the expensive Presidium) is its use is very limited. It can’t distinguish between lab grown material and natural from the earth. The gem testers are best for IDing say CZ vs other gemstones.
On a presidium both sapphire and topaz have the same thermal signature.
given the tone, I’m inclined to think they are sapphires BUT it is another set of tests that determines whether they are lab grown or natural and again whether they are natural yellow or beryllium treated enhanced yellow. Even though the ring is 18ct Gold it is very hard to colour match coloured gemstones, so often times lab grown material is used to ensure the same colour.

 

[MTswirls]

I have the expensive Presidium) is its use is very limited. It can’t distinguish between lab grown material and natural from the earth. The gem testers are best for IDing say CZ vs other gemstones.
On a presidium both sapphire and topaz have the same thermal signature.
given the tone, I’m inclined to think they are sapphires BUT it is another set of tests that determines whether they are lab grown or natural and again whether they are natural yellow or beryllium treated enhanced yellow. Even though the ring is 18ct Gold it is very hard to colour match coloured gemstones, so often times lab grown material is used to ensure the same colour.

Thank you for the information. What do you mean by the tone? Is there a well known difference between the tone of sapphires and topaz? I still have a lot to learn when it comes to gemstones. I remember that my mother originally bought the ring with two other pieces of jewelry that featured colored sapphires, so I suppose that makes it more likely that these are also sapphires, but when I test the other pieces of sapphire I have the diamond tester always goes up to 9 and it only goes to 8 for this ring. Does the price increase a lot for natural gems compared to lab grown gems?
Thank you again for all of your help!

 

[PrecisionGem]

I don't think you are testing the hardness. The tools I have always seen for testing a gem for hardness are a series of what look like pencils. You try to scratch the stone and move up until one of the pencils does scratch the stone. Then you know the hardness. You are using a Presidium device which is designed to separate diamonds from imitations. I don't know any gemologist who actually use these devices, most scoff at them.
Sapphires can be any color from colorless to violet, any color other than red. If red it's called a ruby.

 

[glitterata]

Those electronic testers test thermal conductivity--how quickly the gemstone heats up. Different materials conduct heat differently. It's like how in winter a tile floor feels colder to bare feet than a wooden floor. Diamonds conduct heat extremely quickly, which is why some people touch a suspected diamond to their lips to feel its temperature as a test. (The diamond quickly conducts heat away from your skin, leaving your lip feeling cold.) But other gemstones are closer to each other in their heat conductivity, and sometimes the readings overlap, so it's not a very good way to tell them apart. I recently bought a cheap diamond tester and tried it on my various gemstones. It was good at recognizing diamonds, but it couldn't really tell the difference between glass and garnet or quartz. Sapphires and topaz both have high head conductivity, and they overlap, so it's not a good device for telling them apart.

(Physicists & gemologists, apologies for any errors--feel free to correct me.)

I agree with everyone else that yours are probably sapphires, given the context and the way the color looks on my screen, but to know for sure--and to know whether they're natural or manmade, and any treatments--you'd have to have them tested.

 

[PrecisionGem]

Could be quartz, there is a lot of quartz that is that color. How much did you pay for the ring, that should help you figure out what you have.

 

[MTswirls]

Could be quartz, there is a lot of quartz that is that color. How much did you pay for the ring, that should help you figure out what you have.

I didn't buy the ring. It belonged to my mother so I don't know how much she paid for it, but she wasn't a bargain hunter when it came to buying jewelry. She liked to buy expensive pieces. I was little at the time, but I remember she bought this ring somewhere in the Caribbean with two other pieces of colored sapphire jewelry. Since it was purchased with other sapphire jewelry I assumed these stones might also be sapphires.

 

[MTswirls]

Those electronic testers test thermal conductivity--how quickly the gemstone heats up. Different materials conduct heat differently. It's like how in winter a tile floor feels colder to bare feet than a wooden floor. Diamonds conduct heat extremely quickly, which is why some people touch a suspected diamond to their lips to feel its temperature as a test. (The diamond quickly conducts heat away from your skin, leaving your lip feeling cold.) But other gemstones are closer to each other in their heat conductivity, and sometimes the readings overlap, so it's not a very good way to tell them apart. I recently bought a cheap diamond tester and tried it on my various gemstones. It was good at recognizing diamonds, but it couldn't really tell the difference between glass and garnet or quartz. Sapphires and topaz both have high head conductivity, and they overlap, so it's not a good device for telling them apart.

(Physicists & gemologists, apologies for any errors--feel free to correct me.)

I agree with everyone else that yours are probably sapphires, given the context and the way the color looks on my screen, but to know for sure--and to know whether they're natural or manmade, and any treatments--you'd have to have them tested.

I don't think you are testing the hardness. The tools I have always seen for testing a gem for hardness are a series of what look like pencils. You try to scratch the stone and move up until one of the pencils does scratch the stone. Then you know the hardness. You are using a Presidium device which is designed to separate diamonds from imitations. I don't know any gemologist who actually use these devices, most scoff at them.
Sapphires can be any color from colorless to violet, any color other than red. If red it's called a ruby.

Thank you for the info! I now understand that I was using the diamond tester to measure for thermal conductivity, not hardness. Based off of everyone's input, I'm pretty confident that these stones are sapphires. I know I will need to have them tested to be certain though.