aquamarine or blue topaz how can you tell??

[koko]

Is there a way to tell whether a mounted stone is aquamarine or blue topaz just by looking at it? I bought a 1.8 carat aquamarine stone mounted in 14K white gold, & I''m sure the jeweler is reputable, but I''ve read that even some jewelers have mistakenly purchased a stone that was misrepresented....Mine is princess cut & he did a beautiful job with the setting but I am curious as to how one can know the difference between blue topaz & aquamarine. I didn''t get a certificate or any documentation on the stone, except for a receipt. I wish I had a digital camera, but I don''t. The stone is light - med. blue. Maybe I can take some pictures at my sister''s house this weekend.....Thanks.

 

[Gem Junkie]

Hi Koko,

It''s going to be impossible to differentiate between an aqua and a topaz just by looking at it. But here''s a tip on I.D.-ing your stone.

If you can get your hands on a diamond tester (thermal conductivity), test your stone. If it registers, it''s a topaz. If it doesn''t, it''s an aqua.

Beryl (aqua, morganite, emerald, etc) doesn''t conduct, topaz does.

I hope this helps!

 

[gemnut]

Blue Topaz is usually a much darker blue than aquamarine. I have seen aquamarines that are almost the same color as Blue Topaz but the price for them was waaaaay over what you would pay for a lighter aqua. A bit of green or gray tint is common in aquas, whereas Blue Topaz colors are a much purer navy blue.

Jewelers can''t always discriminate between the two unless they deal often in these stones. I had a jeweler insist that one of my certified aquas was a blue topaz, probably because I didn''t buy it from him - (not that he had any good ones)!

Not that there is anything wrong with Blue Topaz! I love that pure blue color. It''s the value of the 2 stones that are different, and yes, some try to pass off blue topaz as aquas.

 

[Gem Junkie]

Unfortunately, it''s not always easy to tell the difference solely based on color.

Here''s an example:

Last year I went to a gem and mineral show and there was a vendor who literally had a pile of gemstones for sale ($3 per stone). He told me there were both blue topaz and aquamarine in the pile, but he couldn''t identify one from the other.

I picked out a stone that had a beautiful pale blue color (It looked like a nicely colored aqua. In fact, the color was the perfect hue for an aqua...much too pale to be a blue topaz...or so I thought). I was wrong. (Hence my quest to find a method of positively ID-ing between the two.)

It was still worth the three bucks, but it wasn''t what I was hoping for.

Lesson learned: Topaz can come in all colors and saturations.

 

[koko]

Thanks all, for your helpful advice....GemJunkie: I''ll surely be looking for a diamond tester! My (long time) local jeweler is very talented, and as honest as the day is long, but I don''t think he deals much in colored stones. He''s from the "old school" (1960''s/70''s) and also doesn''t work with platinum. The work he has done for me is gorgeous however. He told me he paid his wholesaler $459.00 for my aqua., and paid $50.00 for the 14k white gold head that he mounted it in. (I had the ring already, but he had to remove the existing CZ center stone and customize it)....I guess my next question is where do you go to get stones tested? I also have a pendant that I bought in the Caribbean while on a cruise which was represented as a aquamarine. It''s very pale blue, and is a very large, shallow rectangle cut set in a sterling silver filagree pendent.....I could have cut glass for all I know (I paid $75.00 for it U.S.)......I''m (almost) sure my new ring is a good quality aqua, it''s a med. blue & if I hold it next to something true blue, there is a very faint greenish tint to it....I have an appointment in April with a certified GIA appraiser, but she charges $65.00 for the first item and then $50.00 for each addt''l. item, so I don''t know if this is the correct avenue to follow......for the value of this jewelry.......Thanks Again!

 

[Gem Junkie]

Koko, you and I must have the same local jeweler! My local jeweler knows a lot about diamonds, but doesn’t know very much at all about colored gems (he doesn’t tell his customers that, of course).

As for your pendant, if you think there’s a chance it could be cut glass, the thermal conductivity test won’t help you much (because neither glass nor aquamarine will conduct on the DiamondMate). You’ll need to use another means of identification. (Have you louped it? Can you see any inclusions in the stone?) Even “clean” aquas frequently have some minor inclusions in them (not always, but hey, it’s worth a look).

(As for the greenish tint on your ring, I just bought a blue topaz that has a greenish tint to it in certain lighting …so that’s not necessarily a property only of aquamarine.)

I, personally, don’t send my gems out to get tested, so I can’t help you out there. Sorry.

I’m quite interested in hearing what the results of your testing (both home testing and GIA) are.

Keep us updated!

 

[Amandas_Jewels]

Another way to tell the difference between Blue Topaz and Aquamarine is Refraction. Aquamarine is weakly refracted and will not show double refraction lines as strong as Blue Topaz. Blue Topaz is doubly refractive and will show stronger refraction lines than Aquamarine. What you would do is you would hold the ring, or gemstone at an angle and look down into the gem at the top of the girdle and look for doubling of lines, as if your eyes were playing tricks on you. If the lines are easily noticeable then the gemstone could be Blue Topaz. Correct?

 

[Richard Sherwood]

Koko, the appraiser''s rates sound very reasonable for appraisals.

If you''re not interested in obtaining retail value, but just want to know what your stones are, you might ask her if she does gem ID''s only, at a cheaper rate.

Some appraiser''s will do verbal ID''s at even a cheaper rate.

 

[londonblue]

Date: 4/3/2006 8:53:33 PM
Author: Amandas_Jewels
Another way to tell the difference between Blue Topaz and Aquamarine is Refraction. Aquamarine is weakly refracted and will not show double refraction lines as strong as Blue Topaz. Blue Topaz is doubly refractive and will show stronger refraction lines than Aquamarine. What you would do is you would hold the ring, or gemstone at an angle and look down into the gem at the top of the girdle and look for doubling of lines, as if your eyes were playing tricks on you. If the lines are easily noticeable then the gemstone could be Blue Topaz. Correct?

i was curious exactly how easy it might be to tell apart the difference between the double refraction on aquamarine and topaz so i pulled out both my blue topaz and aquamarine beads, and louped them w/ my new loupe while i could pick out the double lines in the topaz, i don''t think it would be easy for someone to do without having samples both gems to compare to. i felt like i was going blind the other day comparing my sapphire and spinels

but the birefringence is pretty much impossible to see in my aquamarine.