Jewellery Buyer's Guide

At Robert Spotten, Jewellery Design, we want to make sure that you make the right choice when purchasing a piece of jewellery, so we have compiled a guide to help you. Please find below information to help you choose your rings, your gemstones, diamonds etc.

Please contact us if you cannot find an answer to your query, it is most likely other customers have the same questions and we will add our response to our guide.

Choosing your ring size is important as we make to order. Please follow this guide and contact us if you have any queries as some rings cannot be sized.

How to measure your ring size

Ring Size Chart

What different gemstones look like

Guide to selecting your diamonds

At Robert Spotten Jewellery Design, we like our customers to have nice quality diamonds. We have carefully selected our suppliers in order to achieve this even in the case when no certificate is required.

The quality of diamonds we purchase are always a minimum G/H colour and Si clarity. GIA certificates are available on request. GIA certified diamonds tend to be more expensive.


Use the sliding scale to give you an idea on the carat size.

Watch this video supplied by one of the best diamond testing laboratory. GIA certified diamonds are generally more expensive. Other laboratories can certify diamonds but may not be as stringent as the GIA.

follow this guide to selecting your diamond

Attention Different laboratories test and grade diamonds, the most stringent being the GIA. Price of diamonds will be affected by the laboratory which supplied the certificate, GIA certificates being the most expensive.

Other stones look like diamonds. In the past some of our customers have been duped into buying "diamond" jewellery online, thinking they were buying a real diamond. Beware of expressions such as "CZ diamond" or "Manmade diamond" which describe synthetic stones.

White Sapphire

The white sapphire can replace the diamond, with a slightly lesser durability than the diamond.

White Topaz

The white topaz is a semi-precious stone which can look like a diamond but it is softer and therefore less durable.


Moissanite is a synthetic stone with quite a high hardness score, it is the closest imitation to diamond. It can appear more brilliant than diamond and sparkle with more colours when the light enters the stone.

Cubic zirconia (CZ)

Cubic zirconia is a form of zirconium dioxide and is created synthetically. It is the most common diamond substitute but gets easily scratched due to its softness.


A mineral, the spinel can replace a diamond but is even softer than the CZ.


What is Palladium? Palladium is a relatively new precious metal which has proved very popular with our customers:
Palladium has obvious benefits when compared with other white precious metals. It has none of the tarnishing or wear problems associated with white gold; palladium is approximately half as dense as platinum, being 12 grams per cubic centimetre as opposed to 20 grams for 950 platinum, and 16 grams for 18 carat white gold. Palladium used to be a good alternative to platinum or white gold but its price has rocketed in the past 2 years, whereas Platinum has significantly decreased.

What is the difference between 9, 10, 14, 18, 22 and 24 Karat? Red, yellow or white?

Pure gold is made up of 24 karats. As gold is a tender metal, alloys are added in order to strengthen it. The Karat will indicate what percentage of gold is in the metal: for example 9kt gold as 9 parts gold and 15 parts other metals (generally silver and copper depending on the colour obtained).

18kt gold has 18 parts of gold and 6 parts of other alloys.

10kt and 14 kt are mainly found in the USA but we can supply jewellery in those Karats

The colour of the gold will depend on the amount and proportion of copper and silver mixed into the metal. White gold for instance would have a higher silver content.

Explain the hallmark  Robert Spotten has his own hallmark which he puts on his own designs. His hallmark is RS. Please follow this link to learn about Hallmarks in the UK and when a piece of jewellery should have a hallmark. The hallmark in the UK is set inside the ring, we usually ask for the mark to be put in a place where the hallmark will not be affected when the ring is re-sized.

Please read the guide on how to take care of your jewellery, pay particular attention to pearls and porous stones as they are very vulnerable to damage.

How to take care of your jewellery Please read this guide carefully as exposure of some gemstones to chemicals could lead to irreversible damage.

Tips to keep your diamonds sparkling  Please bear in mind that we offer a free engagement ring cleaning service when you purchase your wedding rings from us. Engaged for more than 10 years? then check your setting! if your ring starts "catching" then it may be time to re-tip your ring (change the claws), failure to do this may lead to stones falling out. We carry out repairs in-house so please contact us if your rings need to be re-tipped.

We have found a really good article on buying an engagement ring on the GIA website so we have posted a link to this article. Our own advice is that you need to know what your future fiancee would like, she is the one who will wear the ring. If you are not sure, then we would encourage you to make an appointment for both of you to come and discuss the design you would like. Make sure you know her ring size as some designs are extremely difficult to re-size.



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