Diamonds aren’t forever and neither are those metals: A materials scientist’s guide to getting jewelry right

Say what now? Ok, I’ll slow down. There is so much to love about jewelry, from the gemstones to the gorgeous metals they sit in.

But few people know much about jewelry and what they need to ask their jeweler.

I felt the need to write this, because I’ve seen the consequences of picking the wrong metal for a wedding band firsthand.

My mom got her yellow gold wedding band to match with her yellow gold diamond ring. Even before their 20th anniversary, the damage was done: The band wore away the detail on the side of her engagement ring. Just because they’re the same yellow gold and the same karat, doesn’t mean the metals are the same. The good news is that if you’ve already made this mistake, the damage isn’t super noticeable. My parents have been married 36 years and her ring is still beautiful.

If you want to prevent this, or you want to know more about the different metals, gemstones, and their pros/cons, then welcome to my nerd palace! I’m here to make you sound smart in front of the jeweler.

Key point: if you want to buy your band separate from your engagement ring, remember to ask your jeweler for the metal’s exact alloy information. If not, one ring could rub away detail on the other.

Let’s break some info down in two ways: gemstones vs metals.

Metals

Quick question: What is an alloy?

Quick answer: An alloy is a blend of metals. Alloys are stronger than pure metals.

• Gold

  • Style:

    • Yellow gold is classic & timeless

    • White gold is sleek & modern

    • Rose gold is vintage, popular in the 1920’s

  • Rule of thumb for yellow gold: The higher the karat, the deeper the yellow but also the softer and more expensive the metal. The best thing to do here is shoot for 10k-18k, with 14k being a good middle ground between strength and quality. Yellow gold is the most affordable type of gold.

  • Rule of thumb for white gold: White gold looks like platinum but is much less expensive. However, white gold requires more maintenance than yellow or rose because the rhodium coating wears away with time. It needs to be professionally “re-dipped” in rhodium— a service that takes 1-2 days and is usually not too expensive.

  • Rule of thumb for rose gold: It is Old World glamour mixed with the highest durability of all the gold types but also the most expensive. It’s the most scratch-resistant, meaning it will last the longest.

  • Some science:

    • White gold is yellow gold blended with platinum, silver, manganese, or palladium. Since white gold is still a little yellow, it’s usually coated in rhodium, a strong precious metal.

But wait, another quick question: What does a karat mean here?

Quick answer: In gold, a karat is a measurement of how much gold is actually in the jewelry item. One karat is 1/24 of a whole. When jewelry is 24k, that means 24 out of 24 karats are actually pure gold. This means 24k is pure gold, no alloy involved!

• Platinum

  • Platinum in jewelry is usually 95% platinum and 5% some other mix of metals. So make sure you know the exact alloy before buying that band!

  • It’s more pure than white gold and needs less maintenance but is more expensive and less durable. It’ll scratch more easily than white gold.

  • Because platinum is purer, it is also more hypoallergenic for sensitive skin.

If you’re interested in other types of metals, like titanium, steel, tungsten carbide, or silver, then Google the wedding band metal guide by Jared (not sponsored).

When thinking about prongs, always go for harder metals and at minimum 4 prongs! Don’t lose your gems over this.

My recommended gemstones:

Whether or not you’ve already chosen your gemstone(s), here is a guide for the most popular stones.

Side note: Lab-grown is typically less expensive and always flawless. It comes with the perk that you know the gem was ethically sourced. If you’re going to go with a natural stone, ask where the gem was mined. If they don’t know, it’s probably not a good idea to go with that rock.

• Diamond

  • Timeless, classic, and comes in all colors, a diamond is always a good choice.

  • Diamonds are the hardest natural materials, with a Moh’s hardness of 10/10. They can only be scratched by other diamonds, making them a fantastic choice for longevity.

  • However, diamonds are also brittle, so try not to bang them into anything (for my fellow clumsy kings and queens out there)

• Now for the fun science (and answering Why behind this blog’s title):

  • Diamonds are made of carbon, like you and me! Colorful diamonds come from trace impurities which lend a pop of color.

  • Forged 100 miles beneath the Earth’s crust (or in a lab!) under immense pressure and temperature, diamonds are actually not stable at room temperature and atmospheric pressure. Diamonds are not forever! The diamond you wear on your finger is slowly but surely turning into the exact same “lead” that’s in your pencil: graphite! But don’t worry, the time needed for your diamond to turn into a useful writing tool would take over a billion years.

  • Diamonds are essential to our daily lives without us even noticing it. They’re essential to scientific research, certain audio equipment, and even construction tools!

• Sapphires & Rubies (They’re the same thing! – Kinda)

  • These are both made of aluminum oxide, an extremely strong material at a 9/10 on the Moh’s hardness scale. This is great for those who want a highly durable stone with a different look and feel than diamonds. Note that only diamonds can scratch a sapphire/ruby.

  • They’re less sparkly than diamonds, but still spectacular.

  • While a diamond is $2,500-$30,000 per carat, a sapphire is $50-$10,000 per carat. Cost depends on clarity, carat, and color.

    • From my experience in terms of cost, diamond engagement rings are more expensive than sapphires or rubies.

    • Even though the rest of the internet will tell you that rubies are more expensive than sapphires, I did not find this to be true once I was in the jewelry store!

  • Sapphires & rubies aren’t likely to chip or break.

  • Sapphires and Rubies are forever! Unlike diamonds (see above)

• Some fun science:

  • A pure sapphire is clear like a diamond.

  • Sapphires come in every color.

  • Blue sapphires have titanium and iron impurities.

  • Red sapphires are called rubies. Rubies are red because of the chromium impurities in the crystal.

  • Rubies glow under dark lights! This happens under the sun’s UV rays too, but it’s hard to see. However, this also gives rubies an edge over red diamonds: the glow gives a richer color.

  • Sapphires are essential to every day life too: they’re inside your electronics and are helping advance technology.

• Topaz

  • An 8 on the Mohs hardness scale, they’re also a good choice for durable, long-lasting gemstones.

  • They come in all colors (including clear), with red being the rarest.

  • They aren’t as sparkly as diamonds but are far more affordable.

  • A sapphire/ruby is more sparkly and more durable (in terms of both scratch- and fracture-resistance)

  • A lot of people love topaz for its many meanings: they’re associated with wealth, health, and love in addition to being a birthstone.

    Emeralds (and a little on aquamarine)

  • An 8 on the Moh’s hardness scale, emeralds are also an excellent choice for an engagement ring

  • Even though emeralds are considerably more rare than diamonds, sapphires, and rubies, their lack of popularity as an engagement ring gemstone means they’re actually very affordable, especially lab-grown emeralds.

    • When I was looking at them for my own engagement ring, I tried on an absolutely gorgeous emerald set in white gold that was only $500!

  • Emeralds and aquamarine are made of the same elements and structure, meaning aquamarine is also a good choice for a unique gemstone.

  • Emeralds are less sparkly than sapphires and diamonds, but don’t let that stop you if you love them.

  • Emeralds can be prone to cracking, so be careful and make sure the gem is properly insured.

  • Fun science facts:

    • My biggest reason for loving emeralds, besides the rich green, is their crystal structure: on an atomic level, they look like flowers! A gorgeous structure.

    • Emeralds are green for the same reason rubies are red- chromium is the impurity that makes them so rich in color! It just acts differently in each crystal structure to give those bold colors. In fact, emeralds also glow under dark lights.

    • Aquamarine is blue because of iron impurities

I would not recommend other gemstones for rings due to durability issues. Dishonorable mentions include garnet, opal, moonstone, and pearls. Make sure you pick a stone that will last at least as long as you do, and these are unlikely to meet the task.

When in doubt, ask your jeweler.

With love,

Katie Sautter

Qualifications: Katie holds two degrees in materials science in engineering: a Bachelor’s and a Ph.D.