QUALITY ROUGH

SUNSTONE ROUGH

This is a natural untreated rough specimenfrom Tanzania Africa showing the firey flash it is known for.

It is also known as Labradorite feldspar.

Weight 29.75 cts app

Size  28 x 17 x 12 mm app

Note photo taken with the rough wet.There are natural fractures in the stone[which is common for this type of material] so it will cut smaller stones.Visit SEDA GEMS to see some stones cut from this parcel.

 Sunstone contains inclusions of copper crystals. Sunstone can be found as large as three inches across. The copper leads to varying color within some stones, where turning one stone will result in multiple colors. The more copper within the stone, the darker the complexion

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,tanzania 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.