Gemstone Hardness Guide: Understanding the Mohs Scale

Choosing a gemstone for jewelry is not only about color and cut. Durability matters just as much, especially for pieces you plan to wear daily. The Mohs hardness scale is the industry standard for measuring how resistant a gemstone is to scratching, and it's one of the first things to consider before setting a stone into a ring, bracelet, or earring.

Below is our full reference chart, followed by a breakdown of what the numbers actually mean and how to apply them when choosing or commissioning jewelry.

 

What Mohs Hardness Actually Measures

The Mohs scale runs from 1 to 10 and ranks how easily a mineral can be scratched by another material. Diamond sits at the top with a hardness of 10, while pearl and coral, both organic materials rather than minerals, sit near the bottom at 2.5 to 4.5.

A higher number means a gemstone is harder to scratch. It does not mean the stone is indestructible, and it does not measure resistance to chipping, cracking, or breaking under impact. That distinction is important, and it's covered in the next section.

Hardness Is Not the Same as Toughness

This is the point most buyers overlook. Emerald, for example, has a hardness of 7.5 to 8, which sounds durable on paper. In practice, emerald is naturally included and brittle, so it can chip from a hard knock even though it resists surface scratches reasonably well.

Spinel, by comparison, has a hardness of 8 and is both scratch-resistant and tough, making it one of the more practical choices for daily-wear rings despite being less well known than sapphire or ruby.

When choosing a stone for a piece that will see regular wear, both hardness and toughness are worth asking about, not hardness alone.

Gemstone Hardness by Everyday Wear Suitability

Great for Everyday Jewelry (Hardness 8-10)

Diamond (10), ruby (9), sapphire (9), chrysoberyl (8.5), spinel (8), and topaz (8) are durable enough for rings and pieces worn daily without special precautions.

Suitable with Reasonable Care (Hardness 7-8)

Emerald (7.5-8, brittle), aquamarine (7.5-8), tourmaline (7-7.5), amethyst (7), and quartz varieties including rose quartz, citrine, and smoky quartz (7) hold up well but benefit from settings that offer some protection, particularly for stones prone to inclusions like emerald.

Wear With Care (Hardness 5.5-7)

Peridot (6.5-7), moonstone (6-6.5), opal (5.5-6.5), and turquoise (5-6) are better suited to occasional wear, or to pieces like pendants and earrings that avoid daily knocks and friction.

Best for Pendants and Earrings (Hardness Under 5)

Pearl (2.5-4.5) and coral (2.5-4) are organic gems that scratch easily and should be handled gently, kept away from perfumes and chemicals, and stored separately from harder stones.

Frequently Asked Questions

Can a gemstone with a high Mohs hardness still break?
Yes. Hardness measures scratch resistance only. A stone can be hard and still fracture or chip if it has natural inclusions or is struck at the wrong angle, as is the case with emerald.

What hardness is safe for an everyday ring?
As a general guideline, stones rated 7.5 and above tend to hold up well in rings, provided the setting offers reasonable protection. Stones below 7 are better suited to pendants, earrings, or occasional-wear pieces.

Why is quartz used so often in jewelry despite being mid-scale?
At a hardness of 7, quartz varieties like citrine and smoky quartz are hard enough for regular wear and are valued for their clarity, color range, and affordability.

Does a higher hardness number mean a more valuable gemstone?
Not necessarily. Value depends on rarity, color, clarity, and origin as much as durability. Opal and moonstone, for instance, are prized despite sitting lower on the hardness scale.

Choosing the Right Stone for Your Piece

At Siam Gems Club, we source gemstones directly from mines and first-level dealers across Southeast Asia, and durability is always part of the conversation when we help customers choose a stone for a custom piece. If you're planning a ring, pendant, or bespoke design and want guidance on which gemstone suits your lifestyle and wear frequency, reach out to us and we're happy to advise.

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Rubies

A Glorious Gemstone

The Ruby is the red variety of the mineral corundum and is regarded as one of the four most valuable gemstones in the world due to its hardness and beauty.

The name "Ruby" is derived from the Latin word "rubeus", meaning "red".

While Rubies come in various shades, the market typically recognizes three primary classifications: "Pinkish-Red", "Pigeon's Blood", and "Royal Red". The latter also includes the "Dark Red" Rubies, which are predominantly found in Thailand, Cambodia, and a few East African countries.

The most sought-after and frequently crafted into fine jewelry are gemstones sourced from Thailand, Myanmar, and Sri Lanka. These regions yield the most intense colors and the highest quality gemstones.

The Ruby has captivated humanity for centuries, earning a reputation as one of the most legendary gemstones. Numerous myths and legends have surrounded the Ruby since antiquity; it was said to bring luck and protection against misfortune and evil spirits. Often referred to as the "blood of the earth", the Ruby historically symbolized courage and bravery, while in modern times, it represents love, passion, and energy.

At Siam Gems Club, we showcase the most vibrant hues of this coveted geme. A significant portion of our inventory is sourced directly from the mines in Thailand, with few stones imported from our neighbour Maynmar and through visiting partners from Mozambique and Madagascar. The allure of the Ruby continues to mesmerize, making it a timeless treasure in the world of gemstones.

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Sapphires

The World of Sapphires

Sapphires are a captivating variety of the mineral corundum and rank among the most valuable gemstones in the world. Known for their remarkable hardness and beauty, Sapphires are second only to diamonds in terms of hardness, with Rubies which are red corundums, coming close.

The name "Sapphire" derives from the Greek word meaning "blue". When one thinks of Sapphires, the mind often conjures images of exquisite blue gemstones in various shades. These hues range from sky blue and pastel blues to deep indigo and nearly black tones. Each color typically reflects its geographical origin and is classified into numerous shades. Generally, only blue Sapphires without additional qualifiers are referred to simply as Sapphires.

However, the color spectrum of Sapphires extends far beyond blue. Pure corundum is categorized as a white or colorless Sapphire, also known as "Leuco Sapphire", and serves as an alternative in jewelry to white diamonds.

Meanwhile, the distinction between a pink-red Ruby and a pink Sapphire can be challenging to perceive with the naked eye, despite modern lab techniques providing reliable analyses.

Among the rarest and most sought-after is the Padparadscha Sapphire, showcasing a beautiful pink-orange or orange-pink hue, named after the Singhalesian word for lotus flower. Corundums in gem quality that are neither blue, colorless or red are collectively termed "Fancy Sapphires", marked by their distinct colors such as yellow Sapphire.

The Sapphire holds deep historical significance across cultures, symbolizing power, beauty and loyalty, while also being valued in esotericism and healing practices.

At Siam Gems Club, we proudly offer a diverse array of Sapphires in various colors sourced mainly from Thailand, Cambodia, Laos, and other regions, including Australia and Sri Lanka, alongside exquisite pieces from Africa through our traveling partners.

"In the ancient whispers of Persia, it was said that the earth rested upon a colossal sapphire, its deep azure hue reflecting the boundless sky above."

Handmade by Lianne

Lianne is an artist whose essence flows through every creation she touches. With an innate intuition and profound knowledge of gemstones, she crafts not just jewelry, but talismans imbued with love and energy. Each mala, each bracelet, each piece of beauty she creates is a journey, a meditative experience where time dissolves, and inspiration unfolds.

Lianne understands that these pieces are more than adornments; they are bridges connecting the wearer to their inner self and the universe. With every ornament strung, she channels intention, ensuring that the right jewel meets the right soul. Whether you seek it or it finds you, know that each treasure carries a whisper of the divine, inviting peace and harmony into your life.

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The Significance of Gemstones

Gemstones have held deep meaning for centuries, revered not only for their stunning beauty but also for their powerful symbolism and unique energies. From ancient civilizations to modern-day practices, these precious stones have been believed to possess healing properties, bringing balance and protection to those who wear them. Many cultures associate gemstones with the zodiac, where each stone is said to enhance the traits of specific signs, offering guidance and harmony. Spiritually, gems are thought to help align energies, foster clarity, and support personal transformation.

Understanding the significance of each gemstone can help you choose the best one for your unique needs. Wehther you're seeking healing, spiritual growth, or simply wish to connect with the right energy, this section will guide you in finding the perfect stone that resonates with your inner self.

Let us help you discover the gemstones that truly speaks to you and embrace their transformative power.

Learn about the different stones