I learned SOOOOO much from this man and am the gemologist I am because of his guidance and instruction. THANK YOU, John Koivula!

The video quality may keep some people from watching this, but it is exceptional.

A great example of a piece of quality education. ❤

Surely one of the best , if not the ! About Gems ! Thank you for having done , kept and shown it !!!

Excellent explanation. Thanks for sharing this!

Old But Gold.

Excellent, informative, educational. Thank-you

The EXPERT has spoken.. THANK YOU SO VERY MUCH.

Thank you very much! I love watched .

Thank you thank you so much for sharing and posting.

Wonderful presentation, worth many ships

Very clear and professional classes. I learn more with you. The second name of synthetic rubies is ''french diamonds''. In France, they produce a lot of those ones. Thanks.

Great info

Thank you very much!

awesome explain thanks

Great Job

one of the best gemologists in the world !

Realy great.

Спасибо ребята за этом видео

Hallelujah

how in depth and revealing,sadly the job of gem identification is getting more complex by day,loved this video though,thanks for share

Well now my brain is exploding with information. And I have a ton more questions.

Would anyone know: He mentioned oval cut would be a clue that the ruby is natural; however, would a cushion cut be included with the oval cuts or is it a clue that it would be more synthetic or manufactured?

Please do a series on just vintage jeweler training videos! I love the cut edits at the beginning of this video and the awesome text overlay blue screen! Lol so awesome! I miss the 80’s! The speaker or teacher looks like he is headed to a wedding!! Lol

On Ebay, you can find a 200 carats lab grown, uncut ruby, for under 20$ including delivery. It look like a small half carrot cut in half lengthwise. You can also find cut ruby (real lab grown ruby). Again, under 20$ for 1-20 carats, but the cut is usually pretty poor quality. So, where can I found someone who can cut a bunch of 1-5 carats out of this 200 carats and make it look very good?

Gem mining most of the ruby have fracture need to be filled with glass or other compounds to facilitate grinding. Glass that can be filled with ruby divided according to chemical composition, there are several types as follows: 1. Soda-lime glass 2. Borosilicate glass 3. Lead glass or crystal glass This type of glass has more than 24% lead oxide and has a high refractive index. 4. Opal glass 5. Aluminosilicate glass 6.Alkaline-Earth Alumino silicate 7. Glass-Ceramics 8. Crown glass 9. Flint glass 10. Bismuth glass Because lead glass has good optical properties but is not durable and can dissolve in water, acids, and alkalis when used for a long time. Therefore, choose to buy gemstones that do not contain lead glass and bismuth glass. Other types of glass the quality of gems will be different, such as bismuth glass. However, when purchasing gemstones, you should choose the type that does not contain glass contaminants. and inspected with an X-ray Fluorescence (XRF) machine only because it can determine the amount of lead in percent. To consider the appropriate purchase price.

Are those syntetics is have 9-10 lights level in diamond selector test?

more?

I have this question. When you show the masters some thing. Can the less say any different¿

A very good vid. Its ancient. Note the yellow dot matrix monitor. Synths Sims have come a long way since then. Basic principles still apply. I'd recommend something more up to date. GIA has many.

What difference should it make, if the synthetic ruby is identical in look and chemical composition as the natural ruby?

I have a question though, polychromatically, does a synthetic ruby have same qualities as a natural, because from what I can see it doesn't? Because I've seen a number of synthetic Rubies that are uniform in colour and lack the polychromatic nature of a natural ruby.

There is some sound muted and then turn on, again and again automatically when the background is playing for a half seconds. How can I learn in full video??

Ys the best ruby burma

أود التواصل معك

Looks like a V-2 rocket.

It would need subtitles, along . Not entirely understandable.

if he has eyeglasses he would be tom cruise from tropic thunder 😇

At 27:08 you say you "have also seen Comet Tails in Natural Stones". It would be Prudent to also Provide an image of a Comet tail in a Natural Stone as it would appear there, as well as with any other examples or visuals that appears in both Natural and Synthetic to represent each as they appear in their respective stones. Not having an image of both, would be a good indicator to Skip that particular subject until in an unbias position is established where one can provide such an important example of both scenarios to offer truth and value, to provide complete and non partial information for a professional presentation.

25:57

သင်၏ဗဟုသုတများမျဝေပေးလိုက်သည်

Ok

What could an ethical manufacturer of synthetic stones add as a dopent that would fluoresce in a unique way under UV and yet not alter it's appearance in natural light?

Yyy

Can you tell me what a prise of this...plz

တောက်ပနေသောကျောက်မြက်ရတနာများကြည်နေရသလိုပဲ

66:L6t

Hi I have roby if you are interested

So there isn't any good people in the gem industry to make this law.

Hindi bhasa me bhi batao

So... If you can fool a gemologist with a lab grown stone... What should you pay for a "natural stone"? Lab grown stone have the same crystal structure and component and characteristic of the best stone ever found. They are not involve in conflict They are way more eco friendly (no digging and almost no pollution) Did I mention they are hilariously cheaper!

i have gems

Shi* mine has a scissor cut probably it is synthetic 😢

This should be the same as counterfeiting.its not right it's not moral like a bootleg fake Rolex or Nike shoes.the same penalties should be in place

Too much theoretical, must be breif and to the point