June 25, 2021
Topaz is a mineral one gem variety of which is considered to be cheap and widespread and the other is one of the most expensive and rarest gems in the world. To help understand this stone, navigate its variety and decide on a suitable instance for you. We wrote this manual on topaz assessment factors and we also pay attention to the influence of some nuances on price formation.
The colors of topaz can be varied and have different prevalence in nature and value. In addition pleochroism is characteristic of topaz from weak to strong, depending on the color intensity.
Red is one of the most popular and valuable colors of topaz. Less than a one percent of the total amount of rough materials is going to cut. Red can be not only the main tone of topaz, but also one of the colors of pleochroism.
So, for example, in some orange and yellow stones, faceted in an elongated form of a pear or oval, it appears as an additional shade.
On the photo: red topazes of elongated oval and pear shapes
Pink topaz is very rare; it resembles a fancy diamond and pink sapphire in color. However, much cheaper than these varieties.
Orange is also among the noble varieties. Sometimes it has a light pink hue, so it becomes like a padparadsha sapphire.
If the color is very bright, neon, and the cost is relatively low, most likely in front of you is a topaz coated with a colored film (coated topaz).
Yellow and golden color is more common and comes mainly from the mines of Brazil. The fact that demand for it slightly exceeds supply makes it more affordable compared to red and pink species.
Yellowish brown, brownish tints are often called wine or teahouses. These shades are not stable, they tend to fade in the sun, so their price is low.
On the photo: crystals of wine topaz in the sun
Blue topazes are the most common topaz colors in jewelry. Their popularity is associated with beauty, hardness and the possibility of mass production of blue color. Keep in mind that 99 percent of all blue topazes on the market were irradiated.
On the photo: blue untreated topazes
Colorless (white) topazes are mined in many deposits and often serve as the starting material for the subsequent production of blue color. In the commercial cut colorless topazes do not look attractive, however, being cut in compliance with the necessary proportions, with high-quality polishing, they are very beautiful.
Very rare color for this mineral, the color is not strong, it’s muted. As a rule a greenish color is obtained by superimposing a blue and tan zone in one stone.
Be careful with stones of a strong green color, in most cases these are topazes with a film coating.
Sometimes in the same sample two colors are simultaneously contained. For example, blue and golden brown. If such a crystal is correctly oriented and beat by the arrangement of facets, a faceted stone will have collectible value.
Such topazes are often marketed in the Volynsky field, Ukraine.
On the photo: two-color topaz from Volyn’, Ukraine
Topazes of all colors except blue and colorless, according to the classification of the clarity of GIA classification, are of type II, usually with inclusions. When mining crystals, as a rule, contain mineral, gas-liquid inclusions, etching channels and others.
In some crystals, needle-yellow-brown inclusions are found, which can be mistaken for rutile, however, for verification this can be channels filled with limonite.
As a rule, crystals of rough materials free from defects are selected for cutting. Therefore, faceted topazes are often devoid of eye visible inclusions or imperfections. This is especially true of blue, colorless and yellow topaz, which are more common than pink and red.
In the case of this about 1 percent of recoverable rough materials are suitable for cutting.
Since topaz crystals coming from deposits often have a prismatic appearance, valuable varieties are facet in the form of elongated pears, elongated ovals, baguettes in order to preserve the weight of rough materials as much as possible. Due to their rarity, pink, yellow, red, and orange topazes are practically not faceted in standard sizes.
Colorless, blue and blue topazes are cut in completely different forms, from classic to fancy shapes. Rough materials are common and inexpensive, crystals can reach large sizes and there is no need to “save” to maintain weight. This allows cutters to engage in creativity and dream.
A wide range of sizes of these varieties is presented on the market, from a few millimeters to large interior specimens, both calibrated stones and individual ones. We’ll list the main shapes: oval, round, cushion, trillion, radiant, octagon, heart, baguette, square, marquise, pear.
On the photo: yellow oval cut topazes
White and blue topazes are sometimes found in the form of small calibrated stones, but it should be understand that the cost of cutting work is much higher than the cost of rough materials and they are not used for exclusive jewelry.
This gemstone is very popular, so you can come across imitations or fakes, especially with regard to noble valuable varieties.
Glass is a traditional substance used to create imitations of precious stones. Sitall is a modern and technological variation of special glass. The properties of glass allow you to get a variety of colors, so they can fake many gemstones. What this material gives out is swirls of color zones, bubbles, round and in the form of commas, sometimes quite large visible with the naked eye. When studied in a polariscope, the observation pattern will correspond to an isotropic material or anomalous anisotropy.
It is interesting that the method for producing topaz in laboratory conditions has been developed, but due to the high cost of the work, it is not used in practice for the manufacture of jewelry inserts.
Gem yellow and reddish varieties of topaz are similar to minerals such as spodumene (a variety of tryphan), zircon, tourmaline, citrine, sapphire, heliodor. Zircon gives a bright dispersion, which is not characteristic of topaz. In spodumene, pleochroism is less pronounced. One of the diagnostic methods that makes it possible to determine topaz with high accuracy is the observation of the refractive index in a refractometer.
In yellow topaz, it is 1.61-1.62, in red and pink varieties it is slightly higher than 1.63-1.64. For citrine, which belongs to quartz, it is much lower than 1.54-1.55, for sapphire (mineral corundum), it is higher and amounts to 1.76-1.77.
However, we note that the above methods require skills in working with gemological instruments and specialized knowledge.
The most reliable way to confirm the natural origin of the gem is to contact an independent gemological laboratory.
We give here gemstone report samples on natural topaz.
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