Tanzanite and diamonds are two of the world's most precious gemstones, highly valued for their beauty and rarity. But which one is actually more rare?
Tanzanite is found in only one place on Earth – the Merelani Hills in northern Tanzania, near Mount Kilimanjaro and the city of Arusha. It was first discovered there in 1967 by a Maasai tribesman, and the entire global supply comes from this single small area. In its natural form, tanzanite is a reddish-brown color. It must be heated to 600-700 degrees Celsius to achieve the valued deep blue or violet-blue colors.
In 2002, the Tanzanian government introduced legislation declaring the Merelani Hills a mining exclusion zone and the tanzanite found there a national treasure. Illegal mining is strictly prohibited and all tanzanite stones must pass through government channels before being exported. This policy was established because the limited tanzanite reserves were being depleted at an alarming rate. According to expert estimates, the mines will be completely tapped out within the next 20-30 years.
Meanwhile, diamonds are found on every continent except Antarctica. Major sources include Africa, Australia, Canada, India, Russia, and South America. Diamonds are mined industrially in large open-pit mines and alluvial mines and extracted by hand from secondary deposits. Annual global rough diamond production is approximately 120 million carats, and reserves are estimated to last at least another 50 years at the current mining rate.
So while diamonds are relatively plentiful compared to tanzanite, that doesn't make them common. All natural diamonds are still quite rare. Less than 20% of rough diamonds are of jewelry quality. And large, high-quality colored diamonds are some of the rarest gems in the world. The largest faceted diamond ever found was the 3,106 carat Cullinan diamond from South Africa in 1905. A small fraction of that enormous stone makes up the British Crown Jewels.
But rarity alone doesn't dictate value. Other factors like color, clarity, cut, and carat weight determine the value of individual diamonds. Most commercial-grade diamonds are affordable for use in engagement rings and other jewelry. Only the highest clarity, largest, and most vibrantly colored diamonds sell for millions of dollars per carat.
Tanzanite prices also vary depending on color, clarity, and carat weight. But since the supply is so limited, even lower quality stones sell for $300 to $500 per carat. Top grade tanzanite can cost over $1,000 per carat, with individual gems selling for tens of thousands of dollars.
So, while diamonds are still relatively rare compared to many other gems, tanzanite is undeniably rarer due to its small, finite supply. As the only source of tanzanite nears depletion, prices are expected to skyrocket even higher. Consumers interested in investing in this exceptionally rare gemstone would be wise to acquire it sooner rather than later.
