The mineral name for tanzanite is zoisite, which belongs to the epidote group in mineralogy. As one of the birthstones for December, tanzanite is imbued with a sense of mystery and is widely regarded as an ideal stone for celebrating new beginnings. In earlier times, tanzanite was used primarily as a decorative material. In the 1960s, people discovered blue-violet zoisite in Tanzania and subsequently named it “tanzanite.”

Before diving deeper into tanzanite, let’s first share a little bonus tidbit with you. The “Heart of the Ocean” necklace worn by the female lead in “Titanic” isn’t actually a sapphire—it’s actually a stunning piece of tanzanite. When viewed with the naked eye, tanzanite does indeed resemble a sapphire quite closely. In the retail market, some people even treat tanzanite as a “budget-friendly alternative” to sapphire.
 

Tanzanite has a Mohs hardness of 6–7; generally, gemstones with a Mohs hardness above 7 tend to be more durable. Therefore, when wearing tanzanite, it’s still best to be a bit careful—so long as you avoid knocking it against hard surfaces, it won’t suffer much damage.

Tanzanite’s color is similar to that of sapphire, yet it comes with a price advantage. If you love blue-colored gemstones but want to keep costs under control, tanzanite is an excellent choice. Now, let’s join us as we explore how to select the perfect tanzanite!

How to choose a tanzanite?

First is the color. Tanzanite is a chameleon-like beauty among gemstones, boasting rich hues and strong trichroism. In green tanzanite, the pleochroism manifests as blue, purplish-red, and greenish-yellow; in brown tanzanite, it appears as green, purple, and light blue; and in yellow-green tanzanite, it shows as dark blue, yellow-green, and purple. However, most tanzanites available on the consumer market are shades ranging from pale to medium blue-purple.

Next, let’s talk about clarity. Clarity is one of the key factors to consider when investing in tanzanite. Inclusions refer to mineral crystals, cracks, and other features found within the gemstone. The number and distribution of these inclusions directly determine the gemstone’s clarity level. If the tanzanite contains impurities visible to the naked eye, its value will be significantly reduced—especially for lighter-colored tanzanites, where impurities become even more noticeable.

Another factor that influences a gemstone’s value is its cut. A well-executed cut allows each facet of the gemstone to reflect light, enhancing the brilliance and fire of the stone. Therefore, a gemstone’s dazzling sparkle is inseparable from the contribution of a high-quality cut.

Finally, there’s the carat weight. Under otherwise identical conditions, it’s true that the larger a gemstone is, the greater its collectible value—and tanzanite is no exception. Tanzanite weighing 5 carats or more will be even more valuable as a collector’s item.

Tanzanite boasts numerous advantages. First, its color closely resembles that of sapphire, which significantly enhances its appeal. Second, high-quality, large-grain tanzanite is relatively more common than large-grain sapphire. Therefore, tanzanite does indeed hold certain collectible potential—after all, its elfin-like blue hue is highly prized by jewelry enthusiasts.