Basics of the alexandrite appraisal


 Basics of the alexandrite appraisal

The alexandrite is a valuable semi-precious stone and one of the few gems that can be found in two colors. With its deep red and bluish green hues, this may be one of the most sought after stones on earth.

It is not only this gem’s beauty that makes it so popular, but also its durability. Alexandrites are best known for their resistance to heat and wear. When compared to other precious stones, they are rated as 9 on Moh’s scale of hardness (the higher the number, the more difficult a gemstone will be to scratch or fracture).

Alexandrites are also found in a variety of shapes. They usually have squarish or octahedral crystals which can have striation or modified step-like faces. Common varieties of alexandrite are:

The tabular: Is a flat, rectangular shape that is cut like a diamond and usually has striations running down the corners. It can be found in sizes as small as 1 mm to over 0.5 inches long.

The doubly terminated: Is a crystal that is cut in such a way that the termination at the bottom looks like a corner. It is usually found in medium to large sizes.

The triply terminated: Is also known as the “trigonal crystal” and has three points instead of two. They are usually found in large sizes and are quite rare. Although they are less valuable than doubly terminated crystals, they can be very beautiful, especially when cut into cabochons or faceted jewelry.

The doubly terminated double-terminated: Has an “inverted” termination at the bottom. It is usually found in larger sizes and has a beautiful golden hue.

The chalcedony: Is a crystal that has an irregular shape and can be found in small to medium size. Its color varies from white to gray, sometimes with the merest hint of red or yellow. It may also have striations running across the surface, though these are quite minimal in many cases. Its translucence can range from translucent to semi-opaque.

The azurite: This is a type of chalcedony that has a very faint reddish-yellow tinge to it. It’s quite common and is usually found in sizes between 0.5 and 1 inch long. It can be found in many colors such as red, yellow, green, blue or even purple.

The vesuvianite: Is a translucent crystal that looks like a large cross section of a zirconia. It is one of the most colorfast semi-precious stones available and also has excellent scratch resistance due to its hardness.


When looking to buy an alexandrite, it is very important that you look for a stone that has been properly heat treated. A well-treated stone will give you the best of both worlds – the reds and greens of a natural one, and the durability of an artificial one. You should also inquire with the jeweler about their return policy in case it does not meet your expectations. Remember to be careful when buying alexandrites online or from auction sites – there are many fakes in circulation. Always look for reputable dealers such as Tiffany’s, Garrard’s etc.

It is always very important to know what you are buying before you go ahead with your purchase.

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