Last updated on November 2, 2023
Topaz, the traditional birthstone of November, has been associated with opulence and abundance for centuries. It is a beautiful semi-precious gemstone that comes in various colours and endless shades. Let’s discover a gem that can be an affordable addition to your jewellery collection, suitable for daily wear.
Topaz Origin and Formation
Topaz is found in various parts of the world, and its name is believed to have multiple origins. One theory is that the name “topaz” is derived from the Greek island of Topázos in the Red Sea, which was historically a notable source of this gemstone. Another possible origin is the Sanskrit word “tapas,” which means heat or fire, possibly alluding to the warm, fiery colours for which topaz is known.
Topaz forms deep within the Earth’s crust, typically in association with igneous and metamorphic rock formations. The initial steps in topaz formation involve geological processes such as volcanic activity and the movement of molten material.
Topaz crystals begin their journey when molten lava or magma rises from the Earth’s mantle and eventually cools. As this molten material cools and solidifies, it transforms into igneous rocks like granite, pegmatite, and basalt. These igneous rocks often contain cavities, fractures, and spaces where various minerals can become trapped or crystallize. Topaz formation is closely linked to the presence of specific minerals in these pockets. Common accompanying minerals may include fluorite and cassiterite.
Topaz can also form through hydrothermal processes. This occurs when hot, mineral-rich fluids from the Earth’s interior flow through fractures and cavities in rocks, depositing minerals like topaz as they cool and solidify. The specific conditions of pressure and temperature during the formation process can influence the colour and characteristics of the topaz crystal. For instance, blue topaz may be formed under different conditions than yellow or pink topaz.
Today, gem-quality topaz can be found in various locations around the world. Some of the most notable sources include regions in South and Southeast Asia, Central Europe, North and Central America, Southern Africa, Australia, and Brazil.
Topaz is a remarkable gemstone known for its stunning array of colours, and its colour is undoubtedly one of its most defining features. The wide range of topaz colours is the result of various factors, including the presence of different chemical impurities, the crystal’s structure, and even treatment processes.
Blue topaz is among the most popular and sought-after colours, with shades that can range from pale sky blue to deep, vivid blue. Natural blue topaz is quite rare, and the majority of blue topaz available in the market is created through the heat treatment and irradiation of colourless or pale stones. Well-known blue topaz varieties include ‘Swiss blue’ for lighter shades and ‘London blue’ for deeper, more intense blues.
Imperial or precious topaz stands as the rarest and most expensive topaz variety. It is characterized by its warm, fiery colours, which span from golden yellow to pink-orange. The name ‘imperial’ reflects its historical association with the Russian czars.
Yellow topaz is a classic and popular choice, with hues that can vary from pale yellow to intense golden shades. Some individuals refer to yellow topaz as ‘imperial topaz’ when it displays the characteristic pink-orange tone. Natural pink topaz is relatively rare and highly prized for its delicate to vibrant pink hues, ranging from soft baby pink to vivid hot pink.
Similarly, orange topaz, which encompasses shades from yellow-orange to reddish-orange, exudes a captivating warmth and energy.
Authentic red topaz is exceedingly rare. Some stones with reddish hues are sometimes referred to as ‘imperial topaz,’ but they typically lean closer to the pink-orange spectrum. Brown topaz, often known as ‘sherry topaz,’ boasts a warm, earthy tone, spanning from light brown to deep, rich shades reminiscent of sherry wine.
Green topaz can exhibit variations from pale, minty green to deeper green hues, often due to the presence of chromium or other trace elements.
Colourless topaz, also referred to as ‘silver topaz,’ is transparent and devoid of the impurities responsible for colouration. It shines as a beautiful, sparkling gem in its own right and is often used as an alternative to diamonds.
Some topaz gems undergo artificial treatments that create a captivating rainbow effect. These varieties, known as ‘azotic topaz’ and ‘mystic topaz,’ showcase an array of vivid and shifting colours within the same gemstone.
Clarity is an important aspect when evaluating topaz gemstones, as it directly influences their overall quality and value. Topaz, like many gemstones, can contain internal features known as inclusions. These inclusions are tiny mineral crystals, fractures, or other impurities trapped within the topaz during its formation. Inclusions can vary in size and nature, and they are graded based on their visibility and impact on the gem’s appearance.
Clarity in topaz is typically categorized using a clarity scale that ranges from eye-clean to included, with eye-clean topaz being generally more valuable than those with visible inclusions.
The cut of a topaz gemstone is a critical factor that profoundly influences its overall appearance, brilliance, and value. Topaz, with its unique crystalline structure, offers lapidaries a wealth of cutting possibilities. The choice of cut often depends on factors such as the gem’s shape, colour, and intended use.
Topaz crystals typically exhibit elongated or columnar shapes, which frequently lead to cuts in long oval or pear shapes. This approach not only maximizes the yield from the rough material but also accentuates the gem’s brilliance. In the case of strongly coloured topaz, lapidaries often opt for the emerald cut, a style that preserves the gem’s weight while enhancing its colour, resulting in a stunning visual impact.
The world of topaz cutting is diverse, featuring a variety of cutting styles to accentuate the gem’s innate beauty. Brilliant cuts, characterized by their triangular and kite-shaped facets, create a mesmerizing play of light. Step cuts, with concentric rows of parallel facets, exude a unique and elegant aesthetic. Mixed cuts, combining brilliant-cut crowns and step-cut pavilions, offer a harmonious balance of brilliance and depth. Furthermore, designer-inspired cuts, crafted by both hand and machine, introduce innovative and distinctive shapes to the realm of topaz.
Topaz Carat Weight
Topaz, like many gemstones, comes in a range of carat weights, from small fractions of a carat to several carats.
Topaz gems that are under 1 carat are abundant and readily available. They are commonly used in mass-market jewellery and provide an affordable option for a variety of designs. Topaz in the 1 to 5-carat range is considered mid-sized and offers a balance between size and affordability. Topaz gemstones that exceed 5 carats are relatively rare. As the carat weight increases, the rarity of topaz sizes becomes more pronounced. These larger topaz gems are highly valued, particularly when they exhibit excellent clarity and colour.
Extremely large topaz gemstones, especially those surpassing 10 carats, are exceedingly rare. These exceptional gems are coveted by collectors and connoisseurs for their size and beauty, and they often command premium prices.
|Chemical Name||Aluminium fluorosilicate|
|Colours||Colourless, white, blue, brown, orange, grey, yellow, green, pink, red|
|Hardness||8 on the Mohs scale|
|Refractive Index||1.62 to 1.63|
|Specific Gravity||3.5 to 3.6|
|Transparency||Translucent to transparent|
|Birefringence||0.008 to 0.016|
|Fluorescence||White and blue topaz - weak yellow or greenish glow, brown, pink and yellow topaz - strong orange-yellow glow, red topaz - weak yellow-brown glow|
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