I remember toiling through engineering textbooks in the '70's, being enchanted with the orthoclase feldspar angles of extinction - dextro or laevo, for identification。 They described techniques like immersion in a water medium, probably because optics were not as advanced. I like where you are going with this series of vids, Cheers.
@@Badranghosn good question, but no. The difference needs to be in the separate windows. Two colours in one window would be due to zoning, and doesn’t tell us much.
Very informative! Got a question though...can "color zoning" be advantageous in some applications but dis-advantageous in others??? for example, i had a nice reddishOrange sapphire that was appraised and the appraiser said that it had "unintended" color zoning and therefore it was appraised much lower that i thought it would be(even though the stone is quite nice)...Can you chime in on this ???
Value is a different conversation from identification, for sure. From a commercial/ commodity point of view, many dealers don't prefer colour zoning and choose to view it as an undesirable flaw. Others can find opportunity in zoning if its aesthetically pleasing, and may be able to sell it for more than some other evenly coloured stones. Value at the end of the day is a subjective thing, and comes down to how the item is positioned, and to whom it's marketed, and at what stage in history. Aesthetics change with cultures.
Is it really two distinct colors that we'd see using a dichroscope or two distinct "shades" or intensities of a color ? OR can it be either ? It seems to me that with pink Tourmaline (for example) that we see two separate shades of pink rather than pink on one side and grey or blue (or whatever) on the other side ?
@@SnowTiger45 excellent question~! The critical issue is that the colours in the two separate windows are different. However faint, it’s a distinction for us. If we’re not sure… use a different test. In the left thumbnail of this video both windows have basically the same sets of two colours… that doesn’t tell us much useful information. Two windows with different colours, does.
@GemologyforSchmucks thank you..well in the tomb of the queen of sidon about 800 bc there was a group of natural carved stones i could not buy the 6 stones .one of them was a perfume bottle made of sunstone ..i saw a handle carved in the shape of eagle from ruby
It reminds me of pineal gland in our brain. Calcite, I mean. I bought the tool through Amazon, but I couldn't figure out how to use it, so I retured it 😅 I still have a gem I can't identify. It looks like iolite, shines like beryl, blue to purple, a little gray hue, dark brownish hue from a ceratin angle or in darkness. I don't think it's a Tanzanite. Probably what what was the name... I forgot. I will write it out when I remember...😅
It has inclusions just like emerald. It is about 2 carats oval and set in 18K stamped metal, although tested 14k, and has 2 small chips. I think it's just a lower priced substitute of aquamarine. I love it any way 😊. I just can't remember what I think it is. But I want to know the truth lol
Sounds like an iolite. Testing reflective index is expensive (the refractometer) and a bit tricky to learn (the skills). A dichroscope would be a much lower cost and easy-to-learn tool. Alternatively, you can get a polariscope, it typically lie midway in price but you can do more much more than you can with a dichroscope: detect/observe pleochroism, determine if a stone is singly refractive or doubly refractive, and if doubly refractive, uniaxial or biaxial, polariscope can also provide conclusive evidence for quartz, and provide strong suggestion if a stone could be just glass or synthetic spinel. The downside is most polariscopes are not very portable…unless you buy the more expensive foldable one made by Gem-A (the Gemmological Association of Great Britain).
Thanks again! Great basic refresher.
I'm glad to be of service.
I remember toiling through engineering textbooks in the '70's, being enchanted with the orthoclase feldspar angles of extinction - dextro or laevo, for identification。 They described techniques like immersion in a water medium, probably because optics were not as advanced. I like where you are going with this series of vids, Cheers.
Cheers and thank you.
nice thank you
@@Badranghosn my pleasure~
É uma belíssima gema valeu
@@hitonabreu1618 thank you
if i saw 2 colors in same window is that a doble ref?
@@Badranghosn good question, but no. The difference needs to be in the separate windows. Two colours in one window would be due to zoning, and doesn’t tell us much.
@@GemologyforSchmucks ok this what i thought .i have gemstones books
Very informative! Got a question though...can "color zoning" be advantageous in some applications but dis-advantageous in others??? for example, i had a nice reddishOrange sapphire that was appraised and the appraiser said that it had "unintended" color zoning and therefore it was appraised much lower that i thought it would be(even though the stone is quite nice)...Can you chime in on this ???
Value is a different conversation from identification, for sure. From a commercial/ commodity point of view, many dealers don't prefer colour zoning and choose to view it as an undesirable flaw. Others can find opportunity in zoning if its aesthetically pleasing, and may be able to sell it for more than some other evenly coloured stones. Value at the end of the day is a subjective thing, and comes down to how the item is positioned, and to whom it's marketed, and at what stage in history. Aesthetics change with cultures.
Is it really two distinct colors that we'd see using a dichroscope or two distinct "shades" or intensities of a color ? OR can it be either ?
It seems to me that with pink Tourmaline (for example) that we see two separate shades of pink rather than pink on one side and grey or blue (or whatever) on the other side ?
@@SnowTiger45 excellent question~! The critical issue is that the colours in the two separate windows are different. However faint, it’s a distinction for us. If we’re not sure… use a different test. In the left thumbnail of this video both windows have basically the same sets of two colours… that doesn’t tell us much useful information. Two windows with different colours, does.
@@GemologyforSchmucks in other words...different hues within the same color would be indicative of pleochroism???? ( is my assumption true ?)
i got 2 gems on my youtube
a 46 ct flawless red beryl and a 875ct moonstone.
Sounds like quite the collection
@GemologyforSchmucks thank you..well in the tomb of the queen of sidon about 800 bc there was a group of natural carved stones i could not buy the 6 stones .one of them was a perfume bottle made of sunstone ..i saw a handle carved in the shape of eagle from ruby
@GemologyforSchmucks in balbbak temple they found a blue 1280ct moonstone
It reminds me of pineal gland in our brain. Calcite, I mean. I bought the tool through Amazon, but I couldn't figure out how to use it, so I retured it 😅
I still have a gem I can't identify. It looks like iolite, shines like beryl, blue to purple, a little gray hue, dark brownish hue from a ceratin angle or in darkness. I don't think it's a Tanzanite. Probably what what was the name... I forgot. I will write it out when I remember...😅
@@Jade15888 sounds like iolite is still a possibility then~ an RI would go a long way to help you find the truth.
@GemologyforSchmucks thank you😊 I just can'tremember the name lol.
It has inclusions just like emerald. It is about 2 carats oval and set in 18K stamped metal, although tested 14k, and has 2 small chips. I think it's just a lower priced substitute of aquamarine. I love it any way 😊. I just can't remember what I think it is. But I want to know the truth lol
Sounds like an iolite. Testing reflective index is expensive (the refractometer) and a bit tricky to learn (the skills). A dichroscope would be a much lower cost and easy-to-learn tool. Alternatively, you can get a polariscope, it typically lie midway in price but you can do more much more than you can with a dichroscope: detect/observe pleochroism, determine if a stone is singly refractive or doubly refractive, and if doubly refractive, uniaxial or biaxial, polariscope can also provide conclusive evidence for quartz, and provide strong suggestion if a stone could be just glass or synthetic spinel. The downside is most polariscopes are not very portable…unless you buy the more expensive foldable one made by Gem-A (the Gemmological Association of Great Britain).
@@austinfreyrikrw6651 Thank you 💖