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Red Spinel

Hi
I was wondering if there is any synthetic red spinel ever made?
Are all spinel natural?
would a presidium gem tester tell if the spinel was real or synthetic?
Thank you

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There are indeed synthetic spinels made in every color. They’re commonly used as simulants in jewelry for other more expensive stones. Our spinel gem listing has more info on identifying synthetic spinels. A Presidium gem tester won’t help you distinguish a natural spinel from a synthetic one, or between any natural and synthetic gem, as they make clear on their website. The presidium gem tester measures a stone’s thermal conductivity, so a synthetic gem has the same thermal conductivity as its natural counterpart. It might help you distinguish one gem type from another, but not if the gem is synthetic.

Pedro
IGS Admin

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Thank you for explaining that too me.

Hi,
I read the information that you gave me about synthetic spinels.
Does identifying the gem stones refractive index give a 100% positive result?
Using a refractive index instrument solve the difference between natural, manmade, synthetics?
Thank you

No single test is going to give you a positive identification of a gemstone, but it might help you distinguish it from other gemstones. An RI test won’t distinguish between a synthetic spinel and a natural spinel, since they’ll have the same RIs.

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Synthetic stones are made at the same earth temperature as natural stones, …they are made with the same compasition as natural earth mined stones,…they are real stones, they are hard to distinguish between Natural earth mined and laboritary created stones,.the only difference is one is made faster than the other, the lab created are made in between 12 and 24 hours, Natural earth mined take thousands of years to grow in the rock,…i was reading that some lab created diamonds, are better than Natural earth mined diamonds,…The Synthetic stones are still real stones, they are just not worth as much as Natural Earth mined Stones, but try and distinguish between the 2 is hard, especially if the stones have been fired,…because then you get eye clean stones…

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More on Synthetic stones and natural stones,.Synthetic are all eye clean, they only way toi tell the difference in my opinion is by ultra violet,… with natural stones that have been fired in a kiln, even though they have neem fired they will still hold inclusions, even if they are eye clean, if you look through white light, you will not see any inclusions, but switch to ultra violet, if the stone is natural, it will still hold inclusions, where certain chemicals or minerals have not exploded inside the kiln…i have a 450 carrat african ruby, inside you can only see with ultra violet, it has Gold vains inside it… you cannot see them with white light…

Hi,
Does identifying inclusions ( as most gemstones have an inclusion ) help solve if the gemstone is natural or synthetic or man made?
thank you

Hi
What is the different types of inclusion from natural or synthetic or man made?
Thank you

Synthetic is man made, the room temperature is the same as in natural rock formation… Lab created are made in heated laboritaries, the only difference between the 2 is lab created are not created as set temperature level, so therefore they are not at a specific temperature for a specific type of stone…

so if I can see inclusions in white light and see inclusions in ultra violet light does that mean that the gemstone is natural?
Thank you

Jacobus,
You have great questions. I have seen many stones, natural and synthetic, some labs can put inclusions in the stones to make them look more real. All the ideas of the other posts are great and what I would do too. The only other thing I would rely on is magnification.
Using a scope or a loop. Light the stone from underneath and slowly turn the stone under magnification. Look for the crystal structure, when you can see the stria look yo see if it has angles or a slow curve. If you see curved stria it is synthetic. If you can see angles and growth lines, then it is natural.
You have all the right questions and obviously you want to know more. I would recommend that you take some of the classes or the Gemology program. You won’t be sorry to get the education about gemstones.
Good luck.

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I believe you can distinguish synthetic spinel by its spectrum and placing it on a polariscope will show an anomalous (tabby) extinction pattern.

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Hi
Thank you everyone for answering my questions.

No. Synthetic gems have inclusions. The characteristics of a natural gem versus a synthetic can be very different and help determine if the gem is real or man made. Some times it is obvious and other times it is difficult to tell.

hi.
Thanks.
I have a 6ct red spinel mounted on a 18ct yellow and white gold pendant, the spinel has inclusions : my point is that I thought synthetic gems stones had inclusions Namely Air Bubbles.?
Thank you

Air bubbles would mean that it is synthetic. The absence of air bubbles doesn’t mean it is natural. If there are metallic inclusions, it is synthetic. There are other inclusions in synthetic spinel. To know for certain that it is natural, chemical analysis is needed and that means a professional. There is also the possibility that is a natural spinel that has been heat treated. Heat treatment can leave inclusions as well.

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RE: Synthetic RED Spinel Detection

Red spinels are grown by either the flame fusion technique, or the flux growth method. The flame fusion grown can be detected by refractive index values. RI of flame fusion is lower than the natural red spinel. This is because they can’t quite get the chemistry (stoichiometry) to match.
The flux grown RI however matches that of the naturals. The way most all labs detect any synthetic red spinel (including flux grown) is by observing its spectrum. This is usually seen at the red end of the spectrum where the chromic reaction shows itself as what is referred to as “organ pipes”. The unhealthy organ pipe structure is unique and seen in flux, flame fusion and overly heated naturals.
While the healthy organ pipes (as seen in the natural red spinels) show themselves as very apparent on spectrometers, with training on the proper use of a hand-held spectroscope, many can see the differences between the natural vs lab grown red spinels.

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Hi, I am confusing.
I read some article said that , Synthetic Spinel and Natural Spinel are able to distinguish from RI reading.
Synthetic Spinel actually had higher RI (1.720-1.730) than natural ones (1.718).

According to Bear, flame fusion grown red spinels have a lower RI than natural red spinels. What was the article you found that says synthetic spinels have a higher RI than natural spinel?