 |
The causal colour agent or pigment in Aquamarine is iron, producing like seawater a vast array of subtle shades, from a deep blue to a green blue colour depending on its concentration. The more saturated or intense the colour, the higher the value, though almost all aquamarine has a light body tone, upon which the saturation is overlaid.
Purchasing Aquamarine
Aquamarine as mentioned is coloured by trace amounts of iron that find their way into the crystal lattice, the total concentration of this element is a determining factor in the intensity or saturation of the stone. A highly saturated blue is the most desired colour. Lower qualities can however be enhance by heating to reveal a richer or deeper colour.
Aquamarines of the best quality are eye clean, transparent gems. Some gems can feature inclusions of long, hollow rods, a Beryl family trademark which can reflect light. Asterism a cat's eye or star effect can occur by the aligning of traces of foreign minerals within the stone. A rare feature, this manifests itself in translucent examples of the stones as a six rayed star in a vivid sheen. These rare examples of Aquamarine usually command premium prices.
While Aquamarines can be cut in almost any shape desired, the favored cuts are the simple emerald (step) cut with long or rectangular shapes and the round brilliant cut. Lower quality stones with a high level of translucency are typically cut en- cabochon.
Mineable Deposits
Most, but not all aquamarines are heat-treated to produce the popular blue-green colours from less desirable yellow or pale stones. Lower quality stones are typically heated to 725-850 degrees F (400-450 degrees C) in order to change the colour in favor of the desired, permanent Aquamarine blue.
Important & Famous Aquamarine
While there have been huge finds of Aquamarine with weights of several tons or more, these have always been of non gem quality material due to the weak, gray or opaque colour of the deposits. The largest single find of cuttable quality Aquamarine was made in 1910 in Minas Gerais (Brazil). The stone in question was 243 lb (110.5 kg), 18 inch (48.5 cm) long and 15.5 inch in diameter and was eventually cut into numerous gems of a total weight of more than 100,000 ct.
According to the maritime legend, Aquamarine originated in the treasure chest of mermaids, and since ancient times has as such been regarded as the sailors' lucky stone. Aquamarine is the birthstone for those born in March.
 |
This opaque dark green Chalcedony is also known as Heliotrope from the Greek word for sun turner. During the middle ages magical powers were ascribed to this interesting gemstone, stemming from the myth that the red spots were drops of the Blood of Christ.
Bloodstone was the original birthstone for March, but since 1912, has been replaced by Aquamarine. However, it is still regarded as the astrological gem for Aries.
The green color forming the body of Bloodstone is due to the presence of particles of Chlorite or included hornblende needles in a quartz matrix. The red spots are caused by iron oxide, and not by Red Jasper, as is commonly though. The color is somewhat variable and some specimens of Bloodstone have very little or no red spots
The classic colour for Bloodstone is Green Chalcedony with red spots of Iron Oxide. Bloodstone is a daylight stone; under artificial light the subtle flashed of red are not well displayed. Although this stone is always opaque it is however commonly cut in many facetted shapes such as rounds and pears, in addition to the expected en cabochon cut.
There are no know treatments for Bloodstone. There are many myths and legend surrounding Bloodstone. One myths tells that the red spots were drops of the Blood of Christ. In the Middle Ages many believed it was able to stop hemorrhages by merely touching the stone to the effected part. It was also believed to be able to improved circulation.
No comments:
Post a Comment