An engagement ring is more than a piece of jewelry. It is a daily promise, a constant companion worn through every chapter of a shared life. It will be there for joyful celebrations, quiet moments, and the beautiful ordinary days in between. It is destined to become a future heirloom, a tangible link between generations. Given this profound role, perhaps the most critical question you can ask of any gemstone is: Can it last?

For a gemstone as brilliant and beautiful as Moissanite, this question of durability is paramount. As a modern choice, it naturally faces scrutiny from buyers who have been taught that only a diamond can truly stand the test of time. Can Moissanite handle the rigors of daily life, year after year, decade after decade? Will it scratch, chip, or lose its captivating sparkle?

The answer, backed by the immutable laws of material science, is an emphatic and resounding yes.

This guide is designed to take you on a deep dive into the physical properties that make Moissanite not just a fleetingly beautiful option, but a robustly durable, heirloom-quality gemstone. We will move beyond opinion and into the realm of scientific fact, exploring its hardness, toughness, and stability. Prepare to have any doubts erased and replaced with the confident assurance that Moissanite is, in every sense of the word, a forever stone.

Understanding the Mohs Scale of Hardness: The Science of Scratch Resistance

The first and most famous measure of a gemstone’s durability is its hardness, which is its ability to resist scratching and abrasions. The universal standard for this is the Mohs Scale of Hardness, developed in 1812 by German mineralogist Friedrich Mohs.

It’s crucial to understand what this scale represents. It is an ordinal, relative scale, not a linear or absolute one. This means it ranks minerals from 1 (softest) to 10 (hardest) based on which mineral can scratch another. For example, a mineral ranked at 7 can scratch any mineral ranked 7 or lower, but it will be scratched by any mineral ranked higher. The jumps between the numbers are not equal; the leap in hardness from 9 to 10 is exponentially greater than the leap from 8 to 9.

Let's see where the most important jewelry gemstones rank:

Diamond: 10 — The undisputed king of hardness. As the hardest known natural mineral, a diamond can only be scratched by another diamond.
Moissanite: 9.25 — A definitive and impressive ranking that places it firmly in the highest echelon of durable materials.
Corundum (Sapphire & Ruby): 9 — Also exceptionally hard and durable, long considered a benchmark for precious, lifelong jewelry.

Putting Hardness into Real-World Context

A ranking of 9.25 is impressive, but what does it actually mean for your engagement ring as you go about your day? It means Moissanite is virtually immune to scratching from almost any object you will ever encounter.

Consider the Mohs hardness of common materials:

2.5: Your fingernail
3.5: A copper penny
5.5: A steel pocketknife or nail
6.5: A steel file
7.0: Quartz (the primary component of sand, dust, and granite countertops)
8.0: Topaz or a hardened steel masonry nail

The most common sources of accidental scratches for jewelry are encounters with things like metal doorframes, brick walls, sand at the beach, and granite countertops. All of these materials fall between 5.5 and 7 on the Mohs scale.

With a hardness of 9.25, Moissanite is substantially harder than all of them. This means you can go about your life with incredible peace of mind. An accidental scrape against a wall or countertop will not leave a mark on your Moissanite. This exceptional level of scratch resistance ensures that the pristine surface and sharp, brilliant facets of your gemstone will remain unmarred and beautiful for a lifetime. The only things that could realistically scratch a Moissanite are a diamond or another Moissanite—encounters that are highly unlikely.

While a diamond at 10 is technically harder, the 9.25 rating of Moissanite far surpasses the necessary threshold for a durable, everyday gemstone. For all practical purposes of lifelong wear, its resistance to scratching is absolute and guaranteed.

Resilience: Beyond Scratches to Toughness, Heat, and Chemicals

While hardness is critical, it is only one piece of the durability puzzle. A truly resilient gemstone must also resist chipping, withstand extreme temperatures, and remain unaffected by common chemicals. In these areas, Moissanite’s performance is nothing short of exceptional.

Toughness: Resisting Chips, Breaks, and Fractures

It’s important to distinguish hardness (the resistance to scratching) from toughness (the resistance to chipping or breaking upon impact). A material can be very hard but also brittle. For example, glass is relatively hard, but it shatters easily.

A gemstone’s toughness is determined by its internal crystal structure. Diamonds, while being the hardest material, have a natural internal structure with “cleavage planes.” These are directions in which the atomic bonds are weaker. If a diamond is struck with significant force at just the right angle along one of these planes, it can chip or even split.

Moissanite, with its hexagonal crystal structure, does not have these cleavage planes. This gives it excellent toughness, making it highly resistant to chipping and breaking. It can withstand significant impact from being accidentally knocked against a hard surface. This superior toughness means Moissanite is not just hard, but also remarkably robust and forgiving for those with an active lifestyle.

Thermal Stability: Unwavering in the Face of Heat

Another critical property of a forever stone is its ability to withstand extreme temperatures. This is especially important during routine jewelry maintenance, such as resizing, retipping prongs, or other repairs that require a jeweler’s torch.

Some gemstones are highly sensitive to heat and can be damaged or permanently discolored by a torch. Emeralds, for instance, can be easily fractured by sudden temperature changes. Even diamonds are not invincible; they can burn and turn cloudy at temperatures above 1,500°F (815°C) if not properly protected.

Moissanite, on the other hand, is one of the most heat-resistant gemstones known to man. Composed of silicon carbide, a material also used in high-performance ceramics and electronics, it can withstand temperatures up to 2,000°F (1,100°C) without suffering any damage, discoloration, or change in its optical properties. This incredible thermal stability means you and your jeweler can be completely confident during any future repairs or modifications to your ring. Your Moissanite will emerge from the jeweler's bench as brilliant as the day it was set.

Chemical Stability: Impervious to Daily Life

Your engagement ring will be exposed to a wide array of chemicals throughout its life—from the benign to the harsh. This includes everything from lotions, hairspray, and perfumes to household cleaning agents like bleach and ammonia, or chlorine in a swimming pool.

Some porous or less stable gemstones can be etched, stained, or damaged by these chemicals. Moissanite is chemically inert and completely impervious to such damage. Its stable, non-porous surface will not corrode, tarnish, or react when exposed to any of the acids or chemicals you might encounter in your daily routine. This means you don’t have to live in constant fear of damaging your ring. Its beauty is as stable and unchanging as its chemical composition.

Does Moissanite Get Cloudy? Debunking the Destructive Myth

Perhaps the most persistent and damaging myth about Moissanite is the fear that it will turn cloudy or lose its sparkle over time. This is a crucial concern to address, as the promise of an engagement ring is one of eternal brilliance.

Let's be unequivocally clear: High-quality, modern Moissanite does not, and cannot, become cloudy or lose its optical properties.

The origin of this myth stems from a misunderstanding and a misassociation with inferior diamond simulants, most notably Cubic Zirconia (CZ). Here’s why the comparison is flawed:

The Problem with Cubic Zirconia (CZ): CZ is a beautiful but temporary diamond look-alike. Its primary failing is that it is porous. On a microscopic level, its surface has tiny pores that absorb oils, lotions, soaps, and dirt. Over time, this buildup becomes trapped within the stone, causing it to take on a milky, cloudy appearance that is often irreversible. Furthermore, at around 8.5 on the Mohs scale, CZ is soft enough to accumulate a web of fine scratches from daily wear, which further dulls its surface and diminishes its sparkle.
The Moissanite Reality: Moissanite is a completely different material with a completely different outcome.
1. It is Not Porous: The surface of silicon carbide is stable, dense, and non-porous. It cannot absorb oils or liquids. Anything that gets on the stone stays on the surface, waiting to be wiped away.
2. It is Exceptionally Hard: At 9.25 on the Mohs scale, it resists the micro-scratches that dull the surface of softer stones like CZ.

So, if Moissanite doesn't get cloudy, why does it sometimes look dull? The answer is simple and applies to every gemstone on Earth, including diamonds: dirt.

Over time, a thin film of residue from skin oils, soap, lotions, and everyday grime can build up on the surface of any gemstone, particularly on the pavilion (the angled underside). This film acts like a frosted window, blocking light from entering and exiting the stone, which dramatically reduces its brilliance and fire. A dirty diamond looks just as dull and "cloudy" as a dirty Moissanite.

Luckily, the solution is simple, and the results are immediate. A quick and gentle cleaning is all that is needed to restore your Moissanite to its original, fiery brilliance. A simple bath in a bowl of warm water with a few drops of mild dish soap, followed by a gentle scrub with a soft toothbrush, will instantly remove the residue and bring back 100% of its sparkle.

The promise of Moissanite is this: its internal optical properties are permanent and unchanging. With simple, routine care, your Moissanite will sparkle as brilliantly on your 50th wedding anniversary as it did on the day you received it.

Conclusion: Investing in a Moissanite Ring is Investing in a Lifetime of Brilliance

An engagement ring is chosen with the heart, but it must be trusted with the head. It is an investment in a daily symbol of love, and that symbol must be strong enough to last a lifetime.

The scientific evidence is conclusive. Moissanite is not a fragile beauty. It is a high-performance gemstone engineered for endurance.

With a hardness of 9.25, it is exceptionally resistant to the scratches and abrasions of daily life.
With superior toughness, it resists chipping and breaking, making it a reliable choice for even the most active lifestyles.
With unmatched thermal and chemical stability, it is impervious to damage from heat and common household chemicals.
And with a stable, non-porous structure, its brilliant sparkle is permanent and will never become cloudy or dull.

To choose a Moissanite engagement ring is to choose with confidence. It is an investment in a gemstone that has been proven, both in the laboratory and in the real world, to have the strength and resilience to endure. It is a choice that guarantees a lifetime of unwavering brilliance, a symbol as strong, steadfast, and eternal as the commitment it so beautifully represents.