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Rainbow Moonstone, Cab or faceted?

@Starstruck8 here it is!! I figured the biggest enemy of faceted stone is the light reflection. You can see the huge difference of the stone appearance in attached videos with and without light reflection

While Cab stone doesnt care
 
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@Starstruck8 here it is!! I figured the biggest enemy of faceted stone is the light reflection. You can see the huge difference of the stone appearance in attached videos with and without light reflection

While Cab stone doesnt care

Sorry, I like the faceted stone better, and the other is not Madagascar Rainbow Moonstone, most likely from India. Pretty though.

Plus, the video is somewhat blurred of the Rainbow Moonstone. For that matter the other Moonstone too.

No offence if this is your videos. They just need to be sharper. Sometimes easier said than done.
 
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Sorry, I like the faceted stone better, and the other is not Madagascar Rainbow Moonstone, most likely from India. Pretty though.

Plus, the video is somewhat blurred of the Rainbow Moonstone. For that matter the other Moonstone too.

No offence if this is your videos. They just need to be sharper. Sometimes easier said than done.

Well I love both of them. They are very different to me when I had them compared side by side, and are beautiful in their own way. The India cab are pretty under all light condition, while Madagascar one are picky on the light source but the color is unmatched. Btw finding an Indian moonstone of that quality is much harder than a Madagascar one, so it holds more weights to me naturally. (And the one that I failed to acquire earlier)

Thats the best I can do for videos, its already take in 4k on my iphone. You have to visit me in person if you want to see them in HD. :tongue:
 
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Well I love both of them. They are very different to me when I had them compared side by side, and are beautiful in their own way. The India cab are pretty under all light condition, while Madagascar one are picky on the light source but the color is unmatched. Btw finding an Indian moonstone of that quality is much harder than a Madagascar one, so it holds more weights to me naturally. (And the one that I failed to acquire earlier)

Thats the best I can do for videos, its already take in 4k on my iphone. You have to visit me in person if you want to see them in HD. :tongue:

I understand. It is tough with smartphones. Still, it did not do bad. :)

Though dedicated cameras are the best. Does your smartphone have any type of zoom? I know there are a few on the market now that have some macro capabilities.
 
@Starstruck8 here it is!! I figured the biggest enemy of faceted stone is the light reflection. You can see the huge difference of the stone appearance in attached videos with and without light reflection

While Cab stone doesnt care

Thank you, @LC2016. The colours of the first stone are fascinating. I see your point. Direct reflections from the pavilion facets overwhelm the schiller colours. (This is what I found in the one faceted stone I saw in person.) But when you tilt the stone to avoid the reflections, the colours are amazing.

I think that with the cab, the curved dome (and back?) are 'focusing' the reflection of the light source from the back of the cab to a small area (the bright line in the lower part of the image), so spoils less of the schiller than a whole flat facet would. See this still from the video:
MoonstoneReflection.jpg

As you say, both stones are beautiful in their own way.

This picture from you earlier post is fascinating:
8051EED6-B410-48D7-87EF-7179FC657660.jpeg

It's a similar setup to the one in my 'rainbow' picture. The camera in looking down on the stone, which is lit from the right from a row of windows (see surface reflections). Looking at the top part of the stone, you can see the rainbow sequence, yellow to blue, from right to left. This is evidently the way to make rainbow moonstone cabs show their rainbow!
 
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So I finally got sunlight today and take the moonstone out and the stone is GORGEOUS!!

Frankly these rainbow moonstones looks significantly better under sunlight that they should perhaps be called sunstone.
 
So I finally got sunlight today and take the moonstone out and the stone is GORGEOUS!!

Frankly these rainbow moonstones looks significantly better under sunlight that they should perhaps be called sunstone.

The colours are fantastically bright and strong. They are so bright that they reflect patches of coloured light onto your thumb. It's amazing!
RainbowReflections.jpg
 
The colours are fantastically bright and strong. They are so bright that they reflect patches of coloured light onto your thumb. It's amazing!
RainbowReflections.jpg

Yes! I have discussed with my vendor and we both agreed that rainbow moonstone looks incredibly beautiful (frankly speaking I think its prettier than my jedi spinel) under sunlight, but its sheen is quite weak/ subtle without strong lighting.

Btw, you can adjust the video quality to a higher quality in youtube for a clearer image, I suspect this probably the reason why fred think the video is blurred
 
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Curiouser and curiouser...

I bought a low-quality Madagascar rainbow moonstone to play with. It seems to have three schiller directions, one showing blue and two showing yellow-orange.

Labradorite3D.jpg
(Left - blue. Middle, Right - yellow. Note stone flipped between the yellow pics. Arrows point to the bevels, which show the schiller closest to square-on.)

Why is it so? (As best I can tell, the little cab I showed before appears to have only two schiller directions, one yellow and one blue. This is already puzzling.) A wild guess is that the yellow may be doubled by polysynthetic twinning, in which a sequence of parallel layers have alternating crystal orientations. The next picture at least suggests this:
LabradoriteTwinning.jpg

Note the striations. I thinking these are twinned layers, viewed edge-on. Maybe one orientation is showing blue to the camera and the other isn't? But it would be good to read an authoritative story on this material.

Regardless, it's fascinating. Look at those blue and green clouds!
LabradoritePair.jpg
 
Curiouser and curiouser...

I bought a low-quality Madagascar rainbow moonstone to play with. It seems to have three schiller directions, one showing blue and two showing yellow-orange.

Labradorite3D.jpg
(Left - blue. Middle, Right - yellow. Note stone flipped between the yellow pics. Arrows point to the bevels, which show the schiller closest to square-on.)

Why is it so? (As best I can tell, the little cab I showed before appears to have only two schiller directions, one yellow and one blue. This is already puzzling.) A wild guess is that the yellow may be doubled by polysynthetic twinning, in which a sequence of parallel layers have alternating crystal orientations. The next picture at least suggests this:
LabradoriteTwinning.jpg

Note the striations. I thinking these are twinned layers, viewed edge-on. Maybe one orientation is showing blue to the camera and the other isn't? But it would be good to read an authoritative story on this material.

Regardless, it's fascinating. Look at those blue and green clouds!
LabradoritePair.jpg

I have no idea on the technical terms but oh my they are beautiful
 
I have no idea on the technical terms but oh my they are beautiful

Thank you! Yes, it's spectacular when you light it and view it from just the right angle :). This seems to be pretty typical of rainbow moonstone.

This will probably interest no one but me. but I have confirmed the story about polysynthetic twinning.

In polysynthetic twinning, a series of parallel slabs have alternating crystal orientations. Here is a very brief explanation and picture. There is more information at this website:
PolySyntheric.jpg

In the following picture tells the story:
RMoverlayA.jpg

The camera is looking at the striations edge-on. The camera and stone were fixed while the lighting was moved. In the top left picture, the stone was lit from the left, in the top right picture from the right. The lower picture shows an extreme enlargement of the striations, with the top and bottom bands taken from the left-lit picture and the middle band taken from the right-lit picture.

Note that the left-lit striations and the right-lit striations are complementary: one is dark where the other is bright. So it seems that in this setup the slabs of one orientation are showing blue to the camera when lit from the left and those in the other orientation are showing blue when lit from the right. Without the twinning, only light from one side would make the stone light up. With the twinning, lighting from either side works.

According to the books, polysynthetic twinning is normal in labradorite. Here is a similar demo with a piece of rock shop quality labradorite:LabOverlay.jpg

The setup is similar to the first. Camera and stone are fixed. In the top half, the lighting is in one position, in the bottom half in another. Again, the light and dark areas are complementary. (I have of course chosen the lighting angles to give the strongest effect.)

I think it's very cool to be able to directly observe polysynthetic twinning like this, without any special equipment! YMMV :)
 
@LC2016, this thread prompted me to buy a bigger gem-quality rainbow moonstone cab - 14x12mm, 8.5ct. It's not as bright as @Mrsz1ppy's cab or your stone, but in direct sun, at the right angle, it's very intriguing:
RMSDirectSun.jpg

Lit by the sky in front of a window, it can show a rainbow:
RMSRainbow.jpg

Like the specimen in my posts above, it has three schiller directions, a strong yellow at the side, a weak yellow on top, and blue at the side:RMSBasic.jpg

Like that specimen, it has polysynthetic twinning. But the orientation that causes the strong yellow schiller at the side makes up most of the stone. The other orientation (the one that causes the weak schiller at the top) is confined to a few thin planes. This causes some fascinating effects:
RMSTwinning-1.jpg

These photos, except the window photo, were taken in direct sun. In truth, most of the time and from most angles, the stone looks like a clear dome. But when it catches the light it's fascinating.
 
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