Block of the Week: Emerald

While emeralds are good money in Minecraft, their prices in reality vary wildly because there’s no fixed market. Take the Bahia Emerald, which was mined in Brazil and is one of the largest emeralds yet found, its stone weighing 340kg. But no one can quite work out how much it’s worth. One valuation pegged it at $370 million. It was once put on eBay with a Buy It Now price of $75 million. One offer was made for $19 million. But right now it’s sitting in a Los Angles County Sheriff’s vault, having been recovered after being stolen, and no one can quite work out who owns it.

Still, emerald is pretty special stuff. It’s made out of beryllium, a pretty rare element which is formed when cosmic rays collide. Yes, it’s made in SPACE when particles travelling near the SPEED OF LIGHT crash into each other. And then it becomes part of stars and planets, and...

OH, THE INFINITE MAJESTY OF THE UNIVERSE.

Oh, where were we? Ah yeah, emeralds. So we’ve got a small deposit of beryllium in the Earth’s crust, and now we’re going to heat it to 400 degrees centigrade and apply to it pressure of between 1000 and 3000 kg per square centimetre.

Now, this makes the mineral called beryl. To get emerald, you need a little chromium or vanadium nearby during the process, because it’s these elements that give emerald its green colour. Pure beryl is colourless, after all. In fact, in 13th century Italy, it was used to make the lens of eyeglasses.

You can also get slightly blueish or yellowish emerald if you add the slightest dash of iron, but go too far and you’ll get fully yellow helidor, or light blue aquamarine. Gem experts can get awfully shirty about the distinctions between these different colours, despite them fundamentally being the same stuff.

Hopefully you’re now getting an appreciation for why emeralds are so rare. Beryllium doesn’t often form clumps large enough to form beryl, and then you need just the right amounts of chromium or vanadium around to avoid gem-nerds getting all hoity-toity about the perfection of your gem’s colour.

And even then you don’t know how much it’s worth. Money, schmoney! The important thing is remembering your emerald’s origins: COSMIC RAYS COLLIDING IN SPACE. That’s got be worth something.