Opal vs. Moonstone: Which Glowing Gemstone Is Right for You?

Diamonds sparkle and sometimes even glow (with fluorescence under UV light), but diamonds aren't the only glowing gemstone.

Two of the most popular glowing gemstones are opal and moonstone. While they both have a cosmic quality about them, they are different in every way.

If you’re on the hunt for a new piece of jewelry that has an ethereal quality, you may want to consider either opal or moonstone. Let's examine each of these in detail, to see if either strikes your fancy. 

What is an Opal?

Opals are formed from hydrated silica, meaning they consist of tiny silica spheres that trap both water and light. These spheres scatter light to create a mesmerizing display of shifting rainbow colors—an effect known as play of color, a term unique to opals.

Opals are also known for their magical glow, making them a popular choice for all kinds of jewelry. Two of the most popular varieties are Mexican fire opals and Australian opals, each with unique characteristics. Mexican fire opals, often found in Jalisco and surrounding regions, are formed in volcanic rock and come in bright hues of red, orange, yellow, and sometimes even clear, with flashes of other colors like green and purple. Their freeform shapes and translucent quality make them ideal for statement pieces like earrings and pendants. While some are faceted, most are left in their natural shape.

Fire opals are associated with passion and optimism but, like most opals, are relatively soft and need to be worn and stored with care to avoid damage.

Australian opals, which make up the majority of the world’s opal supply, are known for their brilliant play of color and variety. Found primarily in South Australia and Queensland, they come in several distinct types: black opals, known for their dark body tones; white opals, which feature soft iridescence; boulder opals, which form with a natural rock backing; and crystal opals, prized for their transparency and vivid color play.

Because they’re fragile, Australian opals are usually cut into rounded cabochons and set in protective settings such as a bezel. There are also doublets and triplets, which are thin slices of opal bonded to backing material (and sometimes topped with quartz) for durability and easier setting.

For shoppers on a budget, lab grown opals offer a beautiful, affordable alternative. 

What is a Moonstone?

Moonstone is part of the feldspar family of minerals. It doesn’t have the flash of rainbow colors like opal, but instead it glows with a soft, floating light called adularescence that is blue or white and moves across the stone as the light source changes.

Moonstone is mined in Sri Lanka, India, Madagascar, and Myanmar. The most valuable moonstones are almost transparent with a blue glow, but they are also found in peach and brown tones. There's also the rainbow moonstone, which is actually a labradorite, and has a wider range of color flashes such as blue, purple, and yellow.

Play of Color vs. Adularescence

Although both opal and moonstone produce a glowing appearance, each stone interacts with light differently. Opal’s play of color creates a vivid, almost electric glow with flashes of blue, green, and red that dance across the surface of the stone, giving it a uniquely mesmerizing appearance. This is caused by the silica within the stone that bends the light entering the stone, creating a prism-like, shimmering effect.  

Moonstone’s adularescence is much softer and more subtle. It doesn’t have bright flashes of color across the surface of the stone, but it has a milky glow that appears to be just below the surface of the stone. This is caused by feldspar in the crystal structure of the stone that scatters the light entering the stone. 

Durability

Durability is a key factor when choosing a gemstone for your jewelry—especially if you plan to wear it frequently. To ensure longevity, opt for a stone with good hardness and consider setting it in a protective style, like a bezel, to help shield it from damage.

Opals are a 5.5 - 6.5 on the Mohs scale of hardness, which means they are fairly soft gemstones. They can scratch and chip easily–or even crack if bumped up against something. Opals are also prone to damage if exposed to water or extreme temperatures.

Due to their limited durability, opals are often set in pendants for protection against accidental damage. They must be cleaned carefully with mild soap, with absolutely no ultrasonic or steam cleaning.

Moonstones by comparison are a 6 - 6.5 on the Mohs scale of hardness. Though still considered soft, they are slightly more durable than opals. They too can scratch easily or crack if hit hard enough (internal inclusions make them susceptible to cracking). However, unlike opal, moonstones can weather temperature changes and moisture. This makes them better for everyday wear, though they should still be worn with care.

Symbolism 

Opal has long been associated with creativity, sparking passion and inspiration in those who wear it, Some believe it encourages artistic expression.

In ancient Rome it was a symbol of purity, but in nineteenth century Europe, it became known as an unlucky stone–luckily this is no longer the case. 

On the other hand, moonstone is thought to assist with emotional regulation and positive feminine energy. It's associated with peace and is often worn by people traveling at night to provide protection. Moonstone is popular for jewelry pieces that signify new beginnings, such as weddings or the birth of a new baby.

Final Thoughts

At the end of the day, both opals and moonstones bring a truly ethereal quality to those who wear them.

If you’re drawn to bold color and a dazzling rainbow sparkle, opal might be the stone for you. It’s perfect for someone who wants their jewelry to make a statement. Just keep in mind that opals are a bit delicate, so they shouldn’t be worn on a daily basis. It's best to save them for a special occasion, and make sure they're set in a way that keeps them free of damage.

If you love a softer, more subtle glow, moonstone offers just that. It really is beautiful for a romantic, everyday piece of jewelry. 

Choosing between them boils down to your personal style and how you plan to wear your jewelry. If you’re still unsure, we recommend looking at each in person. Seeing them in person may be all it takes for one of them to steal your heart. And if you love them both equally, there’s no harm in choosing both, as they actually look really beautiful together.