Sparkling powerhouses: Why hardness decides over shine
Do you feel the sparkle when light hits sparkling colored stones? Whether as a symbol of love in an engagement ring, as elegant earrings, or as a highlight in your collection – nothing is more fascinating than a perfectly cut gemstone. But behind the beauty and vibrant color lies a technical criterion that determines everyday suitability and durability: hardness. In this article, we'll take you into the exciting world of gemstone hardness, show you how it's determined, and reveal why you should pay particular attention to it.
What is a gemstone – and what makes it hard?
A gemstone is more than just a beautiful mineral. It has a crystalline form, grows naturally without human intervention, and possesses rarity and resilience. But what does "hard" really mean? It refers to the ability to resist scratches and abrasion. The higher the hardness, the longer the stone retains its polished shine.
A look into history: From the Middle Ages to the present day
In the Middle Ages, colorful gemstones were highly prized. Colorless crystals like diamonds or rock crystal were often overlooked because they appeared plain and were difficult to work with. Only with the advancement of gemology did kings and nobles recognize the value of hardness: A harder material of a harder quality was easier to cut and retained its sparkle forever.
Overview of measurement methods
Mohs hardness scale
The classic among scales: Friedrich Mohs assigned ten degrees of hardness by scratching minerals against each other. A stone that only resists calcification receives a hardness of 3, while a diamond, with a hardness of 10, scratches all others—and remains untouchable itself.
Rosiwal method
More precise, but less common in everyday life: August Rosiwal measured the actual grinding hardness and shows you how much material is removed under defined loads. This creates an accurate picture that goes beyond the rough Mohs impression.
Minimum requirement: hardness ≥ 7
Why seven? Dust contains tiny quartz grains that scratch softer materials over time. However, gemstones with a hardness of 7 and above can withstand daily contact with dust and surfaces. Ruby, sapphire, topaz, and the like easily meet this threshold – tanzanite (6.5) or peridot (6.5–7), on the other hand, should be worn with more caution.
Myth “Indestructible”?
Diamond may be the hardest mineral on earth, but it's not indestructible: It can shatter in a printing press or from a fall. Similar caution applies to emeralds, which, while hard, are fragile due to fine inclusions. For an everyday ring with maximum robustness, diamonds, rubies, or sapphires remain undisputed favorites.
Fun fact to marvel at
Did you know that diamond is about 140 times harder than corundum (ruby/sapphire), 800 times harder than spinel, and even 35,000 times harder than gold? This nonlinearity is what makes the field of hardness so fascinating!
Valoterna in Vienna: Your partner for radiant values
At Valoterna, you'll find hand-picked, natural colored stones with internationally recognized certificates. Our certified gemologists will provide you with personalized advice – from selection to care. Discover gemstones that will not only make your heart shine, but also your investment!