What do diamonds, windows and chalk all have in common? 

They are all gauged by their strength on the "Moh's Scale", which gives a numerical value to each element based on its natural hardness and resistance to abrasion. Ranged between 1 and 10, the scale depends upon the area of indentation made in the material when it's hit with a small steel ball (approximately 2mm in diameter). To give an example, we have started with No.1 being the softest natural element, Talc (Chalk), and finished wih No.10 -- the hardest gemstone in the world, Diamonds.

Moh's Scale of Hardness

1 Talc/Chalk

2 Amber; Soapstone; Bone; Fingernails

3 Calcite; Pearls; Coral

4 Cuprite; Rhodochrosite

5 Mesolite; Chromite; Window glass

6 Turquoise; Strontium; Marcasite; Steel knife

7 Quartz; Garnet; Tourmaline; Tanzanite; Emerald

8 Topaz; Chrysoberyl; Aquamarine

9 Sapphires; Ruby; and substances used as abrasives

10 Diamond

This list should be of particular interest to jewellery owners, as it emphasises the importance of looking after your diamonds, but especially for taking care of your softer gemstones. It is one of the main reasons Calleija offers a lifetime maintenance program with every purchase. As part of our guarantee agreement, all we ask is that you bring your Calleija jewellery in for its complimentary clean and check every six months (and once in the first three months), to ensure your jewellery will be long lasting and treasured for generations to come.


At Calleija, we're often asked, "What is the main difference between an existing design and a bespoke creation?"

John Calleija says, "A personal, bespoke design really is just that -- a personal story, made from elements of the owner, a reflection of them and their jewellery personality. A bespoke design takes into consideration the shapes and colours the owner prefers, with the ultimate aim to pour energy and life into the piece to ensure the gemstones are shown in their best light."

John continues, "It's in the way we set the gemstones, the side details, the top view and everything surrounding the final design. Of particular importance is your gemstone and your personality  — bringing both together in a marriage that lasts a lifetime. But the success of the overall result comes from the enormous amount of time, energy and care that goes into planning your beloved piece of jewellery."

Each element that passes through the Calleija workshop is testament to the supreme dedication, passion and care that becomes a joy for the fortunate receiver. “Bespoke, handmade and individually created with dedication - that’s our passion. In my mind handmade jewellery creations that personalise and reflect your individual style are always treasured for generations to come. It's tangible and intangible - you can feel it, you can touch it, and sometimes it’s hard to explain -- you just know it.” 

A Cut Above

Thank you to our Facebook friend, Talya Jane Goding, for her question to John Calleija:

"What is your favourite cut of diamond?"

JC: When we talk about ‘cut’ in the jewellery industry, we’re really talking about many intricate elements of diamond craftsmanship – facetting, cleaving, crystallisation and polishing, all of which determine the potential of a diamond’s radiance. I am a fan of all beautifully cut diamonds, regardless of colour or clarity. Many people I’ve met over the years have a passion for Emerald, Pear, Radiant and Cushion cuts  -- several others I could add here, it is such a personal preference -- but ultimately the quality of a diamond depends on how well it has been cut and crafted. This is what drove me to create my own custom cut of diamond, the Glacier® Diamond. I took the most beautiful aspects of all traditional cushion cuts and crafted them into one amazing jewel – the Glacier. Glacier Diamonds emulate my passion for bespoke, handcrafted, iconic design and I adore the scintillation, vibrancy and brilliance that radiates from within these incredible jewels. In the past, I have cut mostly White Glacier Diamonds, yet have just recently acquired Champagne and Cognac Glacier Diamonds, destined to become the centerpieces in several Calleija rings. Overall, my life is engrossed by amazing jewels, but to answer Talya's question, my absolute favourite is the Glacier.

Diamond Decisions

Thank you to our Facebook friend, Jessica Putland, for her question to John Calleija:

"What do you personally feel is the most important part of purchasing a diamond?"

JC: I am often asked this question, so it’s important to be able to share with you today, as I know it is foremost in people’s minds when they are considering a diamond purchase for investment or to wear. For me, by far the most important part of purchasing a diamond is to see it in person. Does the shape suit you and your style? Do you like the colour and design? Do you feel a personal connection to it? Perhaps you've seen a beautiful diamond in the window -- I strongly recommend trying it on to see how it feels. Is the piece beautifully made and of the finest quality? If you feel a connection to the diamond, then you know it is special. My second recommendation is to buy your diamond jewellery from someone you trust. When choosing a jewel of any kind, select a well-established jeweller who is passionate about sourcing the finest of gems, one who is authorised to be a true diamond expert. Their designs and unique craftsmanship will also ensure that your heirloom treasure is of the highest quality, and bound to increase in value over time. I could talk about cut, clarity and carat, which are also important but ultimately, all diamonds are different in colour, shape and design, and it’s these individual qualities that make it even more important to see the gem up close. If it exhibits something special, that breathtaking beauty and opulence, it tells you that the diamond is your own personal masterpiece, destined to be yours.