|Dimensions (mm)||not provided|
|Weight (carats)||not provided|
This is a parcel of natural untreated rough specimens from Tanzania Africa
.It is also known as Labradorite feldspar.
Weight of parcel 197.70 cts app
Size of largest 33 x 21 x 10 mm app
This is specimen value and if you would like some better quality material visit our sister site QUALITY ROUGH
Sunstone is a plagioclase feldspar, which when viewed from certain directions exhibits a brilliant spangled appearance; this has led to its use as a gemstone. It has been found in Southern Norway, and in some United States localities. It is the official gemstone of Oregon.
GRADING The first factor in grading is the amount of Schiller[a sub -surface iridescent shimmer]The more schiller the less the stone reflects and shimmers as it blocks suns rays.The next grade is for colour as it can be found in red ,green.yellow,pink and orange.
Sunstone with high amounts of schiller are great for carvings.
The optical effect appears to be due to reflections from enclosures of red haematite, in the form of minute scales, which are hexagonal, rhombic or irregular in shape, and are disposed parallel to the principal cleavage-plane. These enclosures give the stone an appearance something like that of aventurine, whence sunstone is known also as "aventurine-feldspar." The optical effect called shiller and the color in Oregon Sunstone is due to copper. In the middle part of this crystal, it sparks a lot, and usually has a dark color in the middle, and the color becomes lighter as it becomes the outer part.
|Starts||23rd Jan 2017 3:02pm PST|
|Ends||25th Jan 2017 3:00pm PST|
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