Rubies and Sapphires Have the Same Base Mineral

Corundum is a colorless mineral that’s the second-hardest natural substance on Earth, just behind diamonds. While the average person probably doesn’t recognize this aluminum oxide in its pure form, with just a few impurities it becomes a household name. With a touch of chromium, it becomes a ruby, and just a few hints of iron and titanium turns it into a sapphire.

This isn’t a unique phenomenon. Variations of the gemstone beryl, an aluminum silicate, include emerald, morganite, and aquamarine. Some garnets are called hessonite, rhodolite, and andradite. Amethyst is a kind of quartz.

Sought-after color variations of gems like diamonds and topaz also come from impurities. Contrary to what you might think, impurities aren’t always a bad thing!

The Sun Could Someday Turn Into a Giant Diamond

Right now, the core of our sun is a hotbed of nuclear fusion. While some stars explode in a giant supernova and become neutron stars or black holes, our sun is a medium-mass star. After several billion years, it will burst into a red giant, then leave behind its core as a white dwarf.

Here’s where it gets interesting: White dwarfs are one of the highest-gravity environments in the galaxy, with a gravitational field that can be 350,000 times that of Earth’s. This compresses the oxygen and carbon of its core, causing it to crystallize. Diamonds are pure carbon that has crystallized under high pressure. (The ones on Earth formed in the planet’s core and were brought to the surface in ancient volcanic eruptions.) So while there’s some oxygen mixed in, the core of a white dwarf is essentially a diamond.

After decades of theory, in 2013 scientists actually observed this phenomena in the cosmos. Astronomers at the Harvard-Smithsonian Center for Astrophysics identified a 10 billion-trillion-trillion-carat core just 50 light-years from Earth, in the constellation Centaurus. And in 2014, astronomers announced that they’d found an 11 billion-year-old crystallized dwarf the size of Earth.

Modern Birthstones Evolve Based on Marketing

As a concept, birthstones date back pretty far, from the Christian Bible to the mystical gemstones of Hindu tradition. The tradition of wearing a stone for the month you were born began to gel in 16th-century Poland or Germany, likely due to increased trade between Europe and Asia. While these traditional gemstones certainly overlap with modern ones, there are some notable changes: March, for example, was once bloodstone, not aquamarine.

In 1912, however, the birthstone list became a wildly successful marketing tactic. The National Association of Jewelers standardized the 12 birthstones by month, choosing stones that most jewelers could produce and sell easily. That last part is key, and specific birthstones have continued to evolve over the last century.

Many classic, perennial favorites have stayed in place — diamonds for April and sapphire for September, for example. Some months shifted based on color: December has been assigned a wealth of blue stones, from the traditional turquoise and lapis lazuli to the more modern blue zircon, blue topaz, and tanzanite.

Others, like October, have shifted significantly. October’s traditional birthstone is the opal, which is still widely recognized. But in 1952, the Jewelers of America swapped in pink tourmaline to match the rest of the transparent list. As recently as 2016, Jewelers of America added spinel to the August list as part of a marketing campaign.

Amethysts Were Used as Ancient Drinking Protection

Amethysts were so widely used as wards against intoxication or hangovers in ancient times that it’s where they got their name: It comes from “not drunk” in ancient Greek. The actual mythology around the amethyst varies, but many of the stories involve Dionysus, the Greek god of wine, grapes, and drunkenness. In one version, Dionysus becomes enamored with a mortal woman named Amethystos, who was, to put it mildly, not into it. She prayed to her preferred god, Artemis, to help keep her chaste, and in response Artemis turned her into a statue of clear quartz. Dionysus either poured, spilled, or cried wine onto it, staining it purple.

So in 2021, when archaeologists unearthed an amethyst ring from the former site of — what else? — the largest known winery of the Byzantine era, they speculated that its former owner could have been trying to ward off the worst effects of drinking. The team, which had been excavating a site in modern day Yavne, Israel, said that it’s impossible to know for sure.

Garnets Were Named for Pomegranates

While it’s not quite as interesting as “not drunk,” the name “garnet” also has a somewhat decadent origin. In the 13th century, a German theologian named the gem from the Latin word granatus, which means “grain” or “seed,” in this case referring to pomegranate seeds. He wasn’t wrong: A small, oval garnet could absolutely be mistaken for a snack in the right context.

Not All Gemstones Are Stones

While most things we consider “gemstones” are minerals, in practice the distinction has less to do with chemistry and more to do with aesthetics. Calcareous concretions (pearl-like growths from certain mollusks) and pearls are the only gems to grow within living creatures. Precious coral comes from the hardened skeleton of dead coral polyps. Jet is fossilized wood. Amber is fossilized tree resin, and is one of the earliest gemstones to be carved for jewelry. All of these make fine, eye-catching stones, even if they’re missing the crystalline glint of an emerald.

The First Lab-Grown Diamonds Appeared in the 1950s

Lab-grown diamonds have grown in popularity as a more ethical and less expensive alternative to mined diamonds. These diamonds are often called “synthetic diamonds,” even though their chemical makeup is exactly the same.

After more than a century of people trying to figure out how to DIY diamonds, scientists at the General Electric Research Laboratory were the first to announce their success in 1954 — although it took them a second to figure out they did it. After they left their high-pressure equipment on overnight, a blob popped out, but it didn’t look like a diamond. They began to suspect otherwise when the material broke high-end polishing equipment, something only a diamond could do. X-ray tests confirmed their suspicions. It later turned out that Union Carbide and the Swedish company ASEA got there just slightly earlier, in 1952 and 1953, but kept their findings secret.

These small, rough diamonds were great for industrial applications, but they weren’t ready to shine just yet. Higher-quality diamonds appeared in the 1970s, although they were easy to tell apart from natural diamonds under a microscope, and hard to scale. The technology slowly improved, and in the 1990s, diamond industry titan De Beers (who played a pivotal role in our idea of the diamond engagement ring in the mid-20th century) got concerned enough to develop detection machines.

Today, most “synthetic” diamonds are made with a lower-pressure process called chemical vapor deposition, which uses heated gas in a vacuum chamber at extremely low pressures — very different from the high-pressure environment in which diamonds grow inside the Earth.