Let’s Talk Diamonds!
When you start to think about diamonds first understand what is meant by the word ‘Diamond’
Just remember three things.
Diamonds are formed deep within the Earth, 900 million to three billion years ago, brought to the surface by natural forces millions of years ago and mined in only a few places on the Earth’s surface. Some may call diamonds ‘natural diamonds’ or ‘mined diamonds’.
Artificial diamonds can be manufactured in factories using two methods; within machines which create the extreme heat and pressures needed to grow them or in machines which use methane and other gases to grow them. Such products may be called ‘lab grown diamonds’, ‘laboratory grown diamonds’, ‘synthetic diamonds’, ‘man-made diamonds’, ‘created diamonds’. Other terms have been used. Artificial diamonds and diamonds have the same chemical make up, the same optical properties of lustre, brightness and ‘fire’, and the same physical properties of hardness, toughness and density.
There are artificial products that look to the eye at first sight like diamonds but do not have the chemical, optical or physical properties of diamonds or artificial diamonds. These products are called simulants. Examples are glass, rhinestone crystals, cubic zirconia and moissanite.
Global trade associations advise the word diamond should only be applied to those formed in the Earth.
Artificial: “made or produced by human beings rather than occurring naturally, especially as a copy of something natural”
Blog - Diamond Beauty (2) - ‘Life’.
Let’s look at light reflected from a diamond. If you are wearing a diamond (lucky you!) or can see a diamond near you, take a very close look at it now. Without moving the diamond, see if you can see how ‘shiny’ it is, how light is reflected from its surface.
When scrutinising the diamond can you discern its flat surfaces, called facets? There are many having various shapes, varying sizes and are arranged in a symmetrical pattern called the facet arrangement. We shall see later the sizes, pattern and angles between facets contribute greatly to the beauty of diamond.
You see your face when looking in a mirror because all the light falling on it from your face is reflected from the flat mirror surface back to your eyes. When light falls on a diamond almost all enters the gem through the top (crown) facets but a surprising amount doesn’t, it’s reflected back. Some of this reflected light reaches your eyes; you see the facets as shiny surfaces.
How much light is reflected from a gem’s facet in relation to the amount of light falling on it is called reflectivity. Diamond has many superb characteristics as a gem, one of them is its high reflectivity. So high, that when light falls on a diamond facet almost a fifth doesn’t enter the gem, it is reflected back to our eyes creating the ‘shininess’ so loved by many diamond admirers.
Let’s use the word ‘life’ in place of ‘shininess’. We shall see later that the size of the largest facet on top of a diamond, the table facet, greatly influences the amount of ‘life’ of a diamond.
You may have heard the word lustre. Gemmologists use it to describe the appearance of a gem’s surface when it reflects light. Diamond has such a high lustre compared to other gems it has its own unique description: ‘adamantine’ lustre. Most other gems have a glass-like or ‘vitreous’ lustre. The unique lustre of diamond is due in part to its extreme hardness; no other gem comes close to being as resistant to being scratched by other materials. Its superb hardness means it takes an extremely flat facet surface when cut and polished from the uncut ‘rough’ crystal. A very flat facet makes for a great reflecting mirror surface.
Summary:
Diamond is so shiny due to its superb physical (hardness) and optical (reflectivity) properties. Shininess or ‘life’ is seen as light reflected off the crown facets of a diamond. Life is just one component of the famed brilliance of diamond. Most of the light falling on a diamond enters the gem. We shall consider this in the next blog.
Diamond Beauty (1)
Today let’s start exploring the subject of Diamond beauty.
Most jewellery-set diamonds lack colour. They are essentially colourless. Not the entrancing red of ruby or spinel, the calm blue of sapphire or tanzanite, or the arresting green of emerald or demantoid garnet.
Diamond beauty, revealed to our appreciative eyes, lies not in colour but in brilliance.
If you have handled or more probably seen images of unpolished diamond crystals, referred to as rough diamonds in the trade, they look like shiny pebbles. Take a look at my Instagram pic at https://www.instagram.com/p/B_mWInDFMzK/. Yet they are shinier than crystals of other gem varieties but not as much as polished diamonds https://www.instagram.com/p/B_mllfElRw5/
The ‘shininess’ of a diamond is one of their appealing characteristics and part of the makeup of its brilliance. Diamonds display a greater degree of shininess than most other gem varieties.
Why are diamonds so shiny? The answer is in the manner the polished gem interacts with light. Light is essential to display diamond beauty. Two effects can occur when light falls on the flat surface (facet) of a polished diamond; either it is reflected back, shown by this black diamondhttps://www.instagram.com/p/CAus95hFRSh/ or it enters the gem.
In my next blog we shall look at light reflected from a diamond.
Salt and pepper diamonds
I started learning about diamond quality and grading in the late 1970s. At that time in Hatton Garden the clarity system used and taught was not the one formulated by the GIA, now universally utilised, but one predating the American system. Towards the lower end of the clarity scale were the Piqué grades, First, Second and Third Piqué (abbreviated P1, P2, P3). Pique is a French adjective meaning dotted (I was taught it meant ‘pricked’) referring to the spotted appearance of the many eye-visible inclusions within the diamonds. Below the Pique grades were the rarely utilised grades Spotted, Heavy Spotted and Rejection - terms used by a number of cutters and dealers for qualities thought so poor that they had little commercial appeal.
Early on I learnt the Scan DN grading system that listed 1st Piqué, 2nd Piqué and 3rd Piqué was the lowest clarity grades (I considered this system the finest to learn, a grading book illustrating each grade with numerous diagrams was published aiding the tyro diamond grader). CIBJO grading terms introduced in the UK forty years ago had similar low grades of P1, P2 and P3 equivalent to the GIA grades of I1, I2 and I3 (the letter I for Included, although originally GIA used the word Imperfect)
Whatever clarity terms were employed to describe these diamonds containing eye visible light and dark crystals, fractures (feathers) and clouds, such low-grade gems were deemed unattractive so cheap to buy. Yet currently there is a growing demand from jewellery designer-makers for diamonds with ‘character’, ones with unusual and unique characteristics, those displaying obvious inclusions. In the place of the terms Pique or I3 one sees the phrase ‘Salt and Pepper’, referring to the sprinkling of inclusions arguably resembling grains of pepper and salt. A marketing ploy using a catchy phrase to make low grade diamonds appealing.
My video on my Instagram feed shows three such ‘salt and pepper’ diamonds. Gross weight is 1.96 carats, the mid sized diamond is 5.7mm. All are untreated. From my teaching collection I used to show diamond students the appearance of I3 clarity diamonds.
Contact me if you are interested in buying. Smaller similar quality diamonds are available.
Post-Covid buying
How was your Covid lockdown? Are you a little more confident to emerge and get back to a degree of normality? Even if it’s the ‘new normal’?
You’ve probably spent less cash on a daily basis since mid March. Now you wish to spend a little. To loosen the purse-strings a little - a beach holiday perhaps? Of course not - who wants to be confined in a metal tube with strangers for hours? Not a smart move. OK, so spend more on gadgets? Really? How many gadgets do you need, particularly as they are throwaway ‘toys’ you’ll be bored with after a short time?
I’m seeing a movement where folks after enduring months of lockdown are reappraising their lives and wishing for more lasting experiences, emotions and gifts. Many are looking to buy for themselves long lasting jewellery as a reward, a feelgood symbol, a memento of coming through lockdown, celebrating this time now as a marker to remember the immediate past and a beautiful jewel to keep as they look to a better future.
Let me know what you are planning to buy as a reward in the next few months.
Diamond Beauty
Imagine the last time a diamond caught your eye.
Perhaps another person was wearing one at a socially distanced event or workplace. Or your best friend has shown you her diamond engagement ring. Or you have seen a diamond in a jeweller’s shop window as you walked by. Now ask yourself what attracted you to the gem? Was it the size of the diamond? Or its shape? Or something else?
Tell me what excites you about diamond beauty. Comment below.
We shall explore this topic in future blogs.
Any Questions?
Why are you visiting my website today? Perhaps you’ve seen a post of mine on one of my social media accounts? Or your web search has directed you to me? Whatever the reason, you must curious about gems and jewellery.
Perhaps you are a consumer researching a gem or jewellery purchase or you are in the trade wishing to learn more about current trends. Or a journalist looking for some background facts for your next story. Whoever you are, let’s chat.
Go to the Contact page (the link is in the header above) to start our conversation.
Gemmology - what’s that?
It all begins with an idea.
I was at home during week 1 of the UK lockdown due to the COVID19 pandemic, on my terrace enjoying the sun chatting to neighbours in adjacent gardens and balconies. The talk came round, as it usually does when talking to others for the first time, to what we do for a living. One neighbour was a lawyer, others a dentist, a yoga teacher, a non-executive director and business school students. In turn I was asked what I do. “I’m a gemmologist”, I replied to my quizzical neighbours. ‘What’s that?’ said one.
Let's define the word. Gemmology is the study of gems. Wikipedia has “gemmology is the science dealing with natural and artificial gemstone materials.” Note in the US the spelling is gemology.
In the 19th century it emerged as a branch of mineralogy, the study of minerals; most gems are attractive, durable and scarce varieties of minerals (a few gems have an animal (e.g. coral and ivory) or vegetable (e.g. jet and amber) origin. We shall see how the sciences of geology, chemistry, analytical physics and biology are also encountered within gemmology.
I’m a gemmologist. A professional gemmologist. My career has been one of identifying gems and their treatments (Gem Identification) and judging the quality of polished diamonds (Diamond Grading). When I started work in the London gem laboratory in the late 1970s the prime task when testing a gem, whether a diamond or a coloured stone, was to determine its authenticity. That is if it had a natural origin (from the Earth) or if artificial, grown by Man, to look like a natural gem. Pearls were tested to distinguish the rare natural pearl from the more common cultured and imitation pearl.
During my career the testing of a gem developed to include the identification of any treatments to the gem to enhance its beauty hence value. Most gem varieties are routinely treated; various chemical and physical processes are employed to improve colour and clarity. The identification of many modern gem treatments is now more challenging to the gemmologist than testing gem authenticity.
Lately, identifying the geographical (and sometimes the geological) origin of a gem has gained commercial importance as ‘country of origin’ affects the value of some gem varieties. The gem trade attaches more value to scarce fine examples of Kashmir sapphires, Mogok, Burma rubies and Colombian emeralds. Determining where a gem was mined is challenging for a gemmologist demanding the expert use of specialised laboratory instrumentation. Today, the jewellery buyer is asking where and how a gem and the precious metal of a jewellery item has been mined and whether sourcing and trade commerce was transacted in a responsible and ethical way.
To carry out the tasks of a gemmologist, one needs to acquire a thorough knowledge how gems form in the Earth (and how their man-made counterparts are grown), their crystal form, the chemical makeup of the gems, their physical properties, such as hardness, toughness, density and optical characteristics, particularly refractive index, and their behaviour when subjected to various spectroscopic and elemental analysis.
Yet gemmology can extend beyond all these analytical tasks, beyond the physical sciences to art, history, economics and other disciplines. The history of the use of gems in jewellery through the ages and as shown in art since the fifteenth century, their symbolic relevance to diverse cultures; the geology and geography of gem deposits in the world, the economics and social responsibilities of exploration, mining, distribution and pricing of gem materials, the history of gem cutting (lapidary) and of global gem trade routes and marketplaces, all add to the rich field that is modern gemmology.
Do you have a question about gems or gem-set jewellery? Get in touch so we can start a conversation.