My only star is my avatar picture. This was a lucky find for me and a 45th birthday present. The ring is very old as you can see from the bezel being worn around the sapphire. The original shank has obviously been replaced but I adore this ring so much. When I was first considering purchasing I did a Google search and found the attached lab report.
Conventional wisdom is that uniformity is a positive but opacity is a negative. Trade ideal is uniform with just the right amount of translucency. But who cares about trade ideal? More to the point, who can afford it? I love my imperfect stones, because their imperfections point to the processes that formed them.
Sort of, but not precisely. The rutile needles in the silk cause the star, and the density of the silk is usually (but not always) zoned. But the zoning does not in itself cause the star, nor is it necessary for a star.
The orientation of the star is related to that of the zoning. In a round stone lit and viewed square-on, the orientation of the zoning lines will fall halfway between the rays of the star. Put differently, the zoning lines will be perpendicular to one of the rays. You can see this in your stone:
See how the zoning lines are perpendicular to the lower left ray? And they fall between the top left ray and the top right ray. (In oval stones it's not so simple, because the shape of the dome distorts the orientation of the rays.)
The reason? Both orientations are tied to the crystal axes.
Zoning reflects the growth history of the crystal. What we see as lines of zoning are really planes. (You can sometimes see the planes edge-on if you hold a stone at the right angle.) These planes were once the faces of the growing crystal.
The rutile needles too are oriented by the crystal axes. They are formed by exsolution of titanium impurity atoms. At high temperatures the titanium atoms can jump around in the crystal lattice. For energetic reasons, they tend to clump together in long needles with specific orientations in the lattice. As it happens, these orientations are perpendicular to the 3-fold symmetry axis and parallel to the faces. See figures 20 and 21 and nearby text on this page:
https://www.ruby-sapphire.com/index...by-sapphire-inclusions-in-corundum?Itemid=101
In round stones, the rays are perpendicular to the rutile needles, which are parallel to the faces, and hence to the zoning (if present).
Cool fact: In most (not all) black star sapphires, the star is formed by hematite inclusions (not rutile), which are oriented differently. So in round stones, the rays are parallel to the zoning.
Conventional wisdom is that uniformity is a positive but opacity is a negative. Trade ideal is uniform with just the right amount of translucency. But who cares about trade ideal? More to the point, who can afford it? I love my imperfect stones, because their imperfections point to the processes that formed them.
Do you mean the picture on the left?
I'm pretty sure that's ordinary hexagonal zoning. The foreshortening makes the corner look sharper. You can see this in the picture on the right, which is less foreshortened. I'm pretty sure that if you looked at the zoning square-on, the corner would have the 120-degree angle of a hexagon.
It's very cool. The hexagonal zoning reflects the hexagonal cross-section of the crystal as it grew. It is history crystallized, so to speak. It also suggests that the stone was part of a much bigger crystal, with its central axis located somewhere to the left of the stone in the right picture. This is why zoning is so fascinating.
Do you mean the picture on the left?
I'm pretty sure that's ordinary hexagonal zoning. The foreshortening makes the corner look sharper. You can see this in the picture on the right, which is less foreshortened. I'm pretty sure that if you looked at the zoning square-on, the corner would have the 120-degree angle of a hexagon.
It's very cool. The hexagonal zoning reflects the hexagonal cross-section of the crystal as it grew. It is history crystallized, so to speak. It also suggests that the stone was part of a much bigger crystal, with its central axis located somewhere to the left of the stone in the right picture. This is why zoning is so fascinating.
Adding my deep pink beauty. Waiting to get it resized. Can't even wear it at all since it is too big..
Did a PSer buy this? Kicking myself for not bidding. I was sure it would go for much more, and it's a man's ring that would be too bulky for my round little fingers--and I would never have been able to bring myself to ruin that beautiful old J.E.C. setting with its inscription. Still, the stone itself! 4.44 ct of unheated glory! I bet it's amazing in person. WHY didn't I bid????
J.E. Caldwell & Co. vintage 14K YG Natural No Heat Star ruby men's ring size 8 | eBay
This fashionable piece of jewelry is crafted in solid 14K yellow gold and features an approx. 4.44CT Cabochon cut Natural No Heat Star ruby solitaire. This stone is bezel set in a beautifully designed ring.www.ebay.com
Rosa is back from being resized down. I am obsessed with star Sapphires. So magical
Finally got it set.
No diamonds. Just plain white gold. Casual.
I call it my “crown of thorns” ring.
Finally got it set.
No diamonds. Just plain white gold. Casual.
I call it my “crown of thorns” ring.
No diamonds. Just plain white gold. Casual.
I call it my “crown of thorns” ring.
Finally got it set.
No diamonds. Just plain white gold. Casual.
I call it my “crown of thorns” ring.
Finally got it set.
No diamonds. Just plain white gold. Casual.
I call it my “crown of thorns” ring.
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