Gemstones are gorgeous, we already know that. But as we venture into extremes, curiosity strikes and we begin to wonder: What are the rarest gemstones in the world?

Check out 7 of the most sought-after stones on the planet.

1. Red Diamond

Diamonds are already sought after as it is, so you can imagine the gemstone world after the discovery of red diamonds. According to the Sotheby's Auction House, a 1.38ct Red Diamond was projected to be sold for the price of 1.8 - 2.8 million dollars!

2. Grandidarite

This stone was first discovered in Madagascar by (and named after) Alfred Gradidier in 1902. These peculiar stones are typically found in shades of blue and green. Grandidarite are found in so few places in the world today. And although miners have recently found a new mine for Grandidarite in 2014, it is believed that only 300 carats of acceptable stones have been found to this day.

3. Taaffeite

This gemstone was discovered on accident in Ireland by Count Richard Taaffe. At first, he thought that he had discovered a type of spinel, but upon closer inspection, it turns out that the stones properties suggest a different mineral entirely. For example, Taaffeite is doubly-refractive. Double-refraction occurs when light is split into two separate ways with different velocities and different indices. And although they look physically similar, spinel is only singly refractive.

In the trade, Taaffeite is known as Magnesiotaaffeite. And due to it's rarity, it is used almost exclusively as a gemstone. And although it was first discovered in Ireland, Taaffeite is most commonly found in Sri Lanka. Despite that, lower-grade Taaffeite can still be found in parts of Russia and China.

4. Painite

Named for it's founder and British gemologist Arthur CD Pain in Burma (modern-day Myanmar), the Painite is considered the "holy grail" of gemstones by the Guinness Book of World Records. Typically, Painite has a red to brownish-red hue similar to that of rubies or garnets. They were previously thought to have been the aforementioned gemstones until they were later determined to be a new mineral species in the 1950's. According to the Gemological Institute of America, Painite is so rare that there are less than 200 faceted Painites in the world today, most of which are smaller than .40 carats. Painite rough, fresh out of the ground, is usually very included and may contain a lot of fractures, so it makes sense as to why there are so few faceted stones.

5. Red Beryl

In 1958, prospector Lamar Hodges was after Uranium, instead, it found a brilliant red crystal in a mine in Utah. This red crystal was Red Beryl, otherwise known as Red Emerald. Red Beryl gets it's intense red color due to the manganese found in it's chemical makeup. To give you an idea on the rarity of Red Beryl, for every 150,000 diamonds found, 1 crystal of Red Beryl is found.

6. Benitoite

There are debates on who discovered Benitoite first; whether it be JM Crouch or Hawkins and Edwin Sanders. But the stone was discovered near Coalinga, California in 1907. Like the other rare gemstones, Benitoite was once mistaken for another gemstone. It's saturated blue color often mistakes Benitoite for a sapphire. Typically, they come in shades of blue, purple, pink, and if seen from a certain axis, nearly colorless. Lesser quality Benitoites can be found around Quebec, Canada, but it's main source is from California. Benitoite is known as the official state gem of California.

7. Alexandrite

The history of Alexandrite is rich and dates back to Imperial Russia. It was discovered in 1830 in the Ural Mountains of Russia and named after Czar Alexander II who was responsible for emancipating the serfs of Russia and was eventually assassinated. What makes this gemstone particularly appealing is it's natural ability to change color. Under natural daylight, the stone appears greenish; and under incandescent light, the stone appears reddish-purple. It is now an alternative birthstone for the month of June. Click here to shop Jewel Scene's selection of Alexandrite jewelry!

Whether they be super rare or very common, the bottom line is that jewelry is amazing. The formation, the shine, the various colors, all of it. If you'd like to learn more about rare gems, ask your local jeweler! They would be happy to tell you all about these rare stones.