Tanzanite is a rare and impressive gemstone. It is utilized in various jewelry pieces, can come in different cutting styles, and ranges in size from small to large. Despite being discovered only in the 1960s, Tanzanite has become one of the most popular gemstones globally.
Color
Tanzanite is characterized by pleochroism – it changes color when viewed from different angles. Because of this, the cut is a crucial element in determining the primary hue of the gemstone.
High-quality Tanzanite exhibits a vivid blue-purple color with shimmering red-purple tones, seemingly emanating from within the crystal. However, typically these gems are found in a wide spectrum of blue and purple shades. Generally, the brighter the Tanzanite, the higher its price.
Uncut Tanzanite usually shows brownish tones. Most blue-toned stones available on the market today have likely undergone heat treatment, which enhances indigo hues. The initial Tanzanite minerals discovered “in the wild” by the Maasai tribe were also blue. Apparently, they acquired these tones due to the influence of some geothermal source in ancient times.
Since a significant portion of Tanzanite crystals available on the market has been subjected to heat treatment, and this does not affect the gemstone’s characteristics, jewelry experts believe it should not impact the price either. Moreover, even gemological laboratories often cannot determine whether the heat treatment was artificial or natural.
Clarity and Inclusions
Most Tanzanite crystals used in jewelry contain inclusions and defects visible only under a microscope. To the naked eye, the stone appears transparent and clean.
Any inclusions visible to the naked eye sharply decrease the value of Tanzanite. Significant defects in the stone, such as cracks or chips, also have a negative impact on its price.
Cut
The cut plays a crucial role in determining the color of Tanzanite. Due to pleochroism, the specific hue of the stone when viewed from the top depends on how the mineral was cut.
Additionally, cutters consider financial realities before processing the rough stone. Like with other gemstones, losing weight during cutting means losing profit. Transforming a rough stone into a purple-purplish gem requires less trimming than turning it into a blue-purple one. Hence, purple-purplish Tanzanites are more commonly found than blue-purple ones.
However, blue-purple Tanzanites are more expensive than purple-purplish ones, which “balances” the decision regarding the type of cut. Ultimately, jewelers choose between smaller indigo-colored stones and larger purple-purplish ones.
Carat Weight
Tanzanite comes in various sizes, shapes, and cutting styles.
The most beautiful and deep shades are usually observed in large stones – weighing 5 carats or more. Smaller stones often exhibit less intense colors.
