Metal Guide

Because we appreciate the subtle colour of pure precious metals we choose not to plate our fine jewellery and all of our precious jewellery is fully assayed and hallmarked.

The differences between metals of different types and purity is not just the colour difference - which can be quite subtle - but also differences of weight, density and hardness. 

Metal hardness and density

Because pure Gold and Silver are relatively soft in their pure states various other pure metals are added to the gold and silver to increase its durability and strength - which is what the carat (or karat) mark indicates. This is the same for all Silver and Gold not just ours.

We use Silver that is marked 925 which means that it is 92.5% pure silver with the other metals making up the balance.

For our 9ct we use Gold that is marked 375 which means that it is 37.5% pure gold with the other metals making up the balance.

For our 14ct we use Gold that is marked 585 which means that it is 58.5% pure gold with the other metals making up the balance.

For our Palladium we use Palladium that is marked 950 which means that it is 95% pure Palladium with the other metals making up the balance.

For our 18ct we use Gold that is marked 750 which means that it is 75% pure gold with the other metals making up the balance.

For our Platinum we use Platinum that is marked 950 which means that it is 95% pure Platinum with the other metals making up the balance.

The hardness of the metals is a bit more complicated.

Starting with the White metals, Platinum, White Gold and Silver: Platinum is the Mike Tyson, hard as they come. After which 18ct White Gold is then the hardest followed by Palladium, 14ct White Gold and lastly 9ct White Gold which is slightly harder than Silver.

Yellow Gold: 14ct Yellow Gold is harder than 9ct and 18ct Yellow Gold, which are both as soft as each other.

Rose Gold: 18ct is the hardest followed by 14ct which is harder than 9ct Rose Gold.

Diamonds & Gems


All our fine jewellery is handcrafted to the highest standards in our London workshops and we hand select all of our diamonds. We only use quality white diamonds of a high clarity and superior cut that maximises the brilliance, fire and scintillation of the Diamond as well as its carat weight. For Certified Diamonds we supply a GIA (Gemmological Institute of America) or HRD (The Diamond High Council) Diamond Grading Report.

When hand selecting quality diamonds our jewellers adhere to a strict criteria called The 4Cs. As we are particularly concerned about where our materials come from, especially Diamonds, we also have a fifth Ethical Diamonds requirement where we will only use Conflict Free Diamonds.

Diamond Grades

The Diamonds we prefer to use are well above the industry standard for quality. They are as follows: H Colour VS1 or VS2 Clarity - A near colourless Diamond with discrete,verysmall inclusions that can be detected by an expert with varying degrees of difficulty. E Colour VS1 or VS2 Clarity - A rarer colourless certified Diamond with discrete, very small inclusions that can be detected by an expert with varying degrees of difficulty. D Colour VVS1 or VVS2 Clarity - A truly colourless certified Diamond with extremely discrete, very, very small inclusions that can be detected by an expert with varying degrees of difficulty under 10x magnification.
These high quality Diamonds are either GIA or HRD certified above 0.40ct. Diamonds that are below 0.40ct are non certified unless requested.

The 4Cs

When hand selecting quality Diamonds our jewellers adhere to a strict criteria called The 4Cs, which stands for Colour, Clarity, Cut and Carat.


Colour is one of the most important characteristics that determine the value of a Diamond. An ideal Diamond is totally absent of all body colour (colourless), unless you desire a rare Fancy Diamond that comes in the fully saturated colours of yellow, pink, blue, green, champagne, black, and very rare red.Diamonds are graded on a precise colour scale established by the Gemmological Institute of America (GIA) and range from totally Colourless (D to F) and Near Colourless (G to J), down through a progression of tinted and lighter yellow colours (K to Z). Fancy Diamonds - where an intensive hue is an asset - range from Fancy Light, Fancy to Fancy Intense. At Stephen Einhorn we like to use premium quality Colourless Diamonds ranging from D to H.


The Clarity of a Diamond refers to its optical quality owing to the presence of inclusions (internal objects) and blemishes (external marks) that can be seen under magnification or 10x Loupe. The fewer and less prominent the inclusions, the rarer and thus more valuable the Diamond. Almost all natural diamonds contain their own variation of these inclusions that are minute traces of non-crystallised carbon or small non-diamond crystals, making every Diamond unique. The grading of Clarity is based on a standard Clarity Grading system, with the extremely rare Flawless (FL) being at the peak of the scale.


The quality of the Cut can have the greatest effect on the value of a Diamond. The proportions and symmetry of the facets cut from a rough diamond will establish its light performance, thus determining the polished Diamonds brilliance, sparkle, and fire. As the polishers skill in shaping the stone is paramount the Cut is the one factor most directly influenced by man. A well-cut diamond will internally reflect light from one mirror-like facet to another and disperse and reflect it through the top of the stone in a rainbow blaze. A badly cut Diamond, such as one that is cut too deep or too shallow, will leak light out through the base or side of the Diamond, thus diminishing its brilliance and value. As all of our fine jewellery is handmade in the London-based Stephen Einhorn workshops, only those that provide the most dynamic light show are hand selected by our jewellers. The Cut is not to be confused with the Shape or Style of the Diamond, which you can read about in our Shape and Style section of this guide.


Carat is the standard international unit of weight for Diamonds and does not refer directly to the Diamonds size. However, as larger Diamonds occur less frequently in nature they can be more valuable, but only depending upon their rating with the other 3Cs. It is vitally important that colour, clarity and cut are also taken into account when selecting a Diamond for aesthetic appeal, quality and value. Two stones of equal size can have very different values depending on their quality. Carat weight does not affect the value in diamonds proportionately and the larger the stone the more disproportionate the increase in cost per carat. 1 Carat = 1/5 (0.2) Gram. The Carat is further divided into points; a unit of weight used only for Diamonds. 1 Point = 1/100 (0.01) Carat. When hand selecting Diamonds we take into account all of the 4Cs. We prefer quality white Diamonds that display the greatest brilliance, fire and scintillation. If you require a particular size Diamond of a particular Carat weight, Colour, Clarity, and Cut we can source this for you as part of our Bespoke Jewellery Service.

Conflict Free

Conflict Diamonds are rough diamonds that are traded illicitly by rebel movements in many parts of West and Central Africa to purchase arms and fund brutal military campaigns. These insurgent groups perpetrate violent atrocities and human rights violations against innocent civilians and prolong civil wars. The Kimberley Process Certification Scheme is an international, voluntary system that bans the trade of Conflict Diamonds and imposes extensive requirements on Participants to certify that shipments of rough diamonds are free from Conflict Diamonds. We choose to comply with the United Nations backed Kimberley Process Certification Scheme and refuse to use Conflict Diamonds. We also insist that our suppliers provide us with written guarantees, ensuring they do the same.We offer this pledge on behalf of the millions of innocents who have suffered displacement, maiming and death at the hands of the rebel groups who have been funded by illicit diamond proceeds. Back to top


Naturally formed gemstones come in a large range of types, in a huge variety of colours and cuts, from many parts of the world. As all items from our London workshop are handmade using ethically sourced materials and labour  we hand select all of our quality coloured gemstones from the huge choice available. Our gemstones are carefully chosen for their liveliness, richness & evenness of colour and aesthetic appeal. Any gemstone that does not meet our high standards is immediately rejected. We only use reputed gem dealers who keep a close check on the conditions under which their natural coloured gemstones are mined. Our precious stones are as ethically sourced as possible.As we are particularly concerned about where our materials come from, especially diamonds, we also have a fifth ethical requirement where we refuse to use conflict diamonds which are inexorably linked with human rights abuses and conflict in many parts of Africa. We do not buy or use rubies from Myanmar due to the ongoing situation of  the Rohingya people. It is not acceptable to ignore these abuses of human rights.Back to top


Stephen's designs capture the essence of modern urban life. The smooth, clean lines of his Gypsy and Rub-Over settings, where the Diamond or Gemstone is flush with the top of the ring, means there are no prongs or claws to become caught or bent unlike many traditional settings. Stephen prefers to use a mixture of modern classic shapes and styles of Diamonds and Gemstones to complement his contemporary and minimalist designs.On special request, Stephen will design custom-made settings for other Shapes & Styles of Diamond and Gemstone cuts as part of our Bespoke Design service.


Stephen Einhorn offers a bespoke jewellery service where we design and hand make commissioned pieces on special request. Bespoke engagement rings using premium quality Diamonds and Gemstones in custom-made settings are our particular specialty. To take advantage of this service please refer to the Bespoke Quote section of this website. Our specialist jewellers will be able to advise you as to the best quality Diamond to suit your tastes, requirements and budget.


Diamonds are the hardest substance known to humankind and your Diamond should last forever with the right care. Coloured Gemstones are more fragile and also require special care. Therefore we advise you to take note of our Diamond and Gemstone jewellery care advice in the Jewellery Services section of this website.