December

PRIMARY: TURQUOISE - "The stone to represent the sky is alive on earth"

Turquoise, the primary December birthstone, is a semi-precious gemstone with a hardness value between 5.0 and 6.0.

Here's an article written for us by the jewelry designers with the De Mi A Ti collection to give you more information about turquoise:

Value

Hardness and richness of colour are two of the major factors in determining the value of turquoise; while colour is a matter of individual taste, generally speaking, the most desirable is a strong sky to "robin's egg" blue. In Tibet, however, a greener blue is said to be preferred. Also, sleeping beauty is another favorite type.

The mother rock or matrix in which turquoise is found can often be seen as splotches or a network of brown or black veins running through the stone in a netted pattern, is referred to as spider webbing. The name alludes to a pattern of tracings of color, ranging from black to red, due to infillings of another mineral-iron oxide. Spider webbing occurs when iron oxide, which can range in color from black to reddish, fills in cracks in turquoise.

The pattern is always random, with the individual strands ranging in thickness from hair-thin to coarse bands. There is no pattern to spider webbing, as the contrasting lines wander through the turquoise, crossing, curving and ending abruptly. Such contrasting lines are attractive and raise the value of the turquoise.

Sometimes the contrasting iron oxide is seen in small rounded blotches or thick bands or layers. A good lapidary artist can use such contrast to his or her advantage, incorporating it into the overall artistic effect of the stone.

The chemistry of turquoise reveals its origins. It is found only in or near copper deposits, as it depends on the presence of copper ions for its formation. Turquoise also depends on its host rock to provide two other critical ingredients in addition to the copper ion. They are aluminum ions and the phosphate radical. A trace of water completes the structure. Any number of copper minerals can supply the necessary main ingredient.

Turquoise is treated in many different ways, some more permanent and radical than others. Controversy exists as to whether some of these treatments should be acceptable, but one can be more or less forgiven universally: This is the light waxing or oiling applied to most gem turquoise to improve its colour and lustre; if the material is of high quality to begin with, very little of the wax or oil is absorbed and the turquoise therefore does not "rely" on this impermanent treatment for its beauty. All other factors being equal, untreated turquoise will always command a higher price. Bonded and "reconstituted" material is worth considerably less.

Care

Turquoise is inherently fragile and sensitive to solvents; perfume and other cosmetics will attack the finish and may alter the colour of turquoise gems, as will skin oils, as will most commercial jewelry cleaning fluids. Prolonged exposure to direct sunlight may also discolour or dehydrate turquoise.

Care should therefore be taken when wearing such jewels: cosmetics, including sunscreen and hair spray, should be applied before putting on turquoise jewellery, and they should not be worn to a beach or other sun-bathed environment. After use, turquoise should be gently cleaned with a soft cloth to avoid a build up of residue, and should be stored in its own container to avoid scratching by harder gemstones. Turquoise can also be adversely affected if stored in an airtight container.

Alternate: Blue Topaz

Blue topaz, the alternate December birthstone, is a semi-precious gemstone with a hardness value of 8.0. See November's primary birthstone description for topaz details.