My week at the jeweller’s bench.

Never say Never… I was never going to send my daughter to Boarding School and then it happened….I needed to occupy myself for the first week after she left….what better place to hang out than on a Central St Martin’s short course…
Jewellery and Wax Carving.


Kings Cross campus is a fantastic venue, especially in the sunshine…the new space is perfect to work in and the teaching is first class.


Gems and fine jewellery rarely reflect the industrial workshop that they are created in…..making jewellery is very physical…sawing, carving, filing, hammering, soldering…however the joy of St Martin’s is that they have a tool (or several) for every part of the process.


Wax carving appears child’s play however the technique took a couple of days to master and by then you have made several mistakes which take time to fix. I absolutely love working at a jeweller’s bench and having a week dedicated to thinking and creating was such a luxury.  My first project was a commission from my 17 year old son.  He had a very specific ring he wanted and this was the perfect opportunity to realise that dream. He was thrilled with the result and has been proudly showing all his friends. Helping him to identify his style and then spending the time to make it perfect has been a very rewarding experience.

Other pieces I designed and created were made using fine sheets of wax and layering them up to make different shapes. I had an idea which morphed into a floral pendant and then a more delicate ring….I cast these in silver, however I can see the ring being made in rose gold with a little diamond set in the centre of the flower. I am interested to hear your feedback as this might become the beginning of my first range…


Sarah x


The result of a day in the Garden, Hatton Garden that is…

Well a funny tweet started today’s blog….I have spent the morning in the Garden….and it has nothing to do with horticulture…. Working as a bespoke jeweller is never dull…every request is so incredibly different and personal.  I learn from every project and enjoy educating my clients  about the piece of jewellery that they are making….

Focal point: the pink diamond

This week has involved selecting natural pink diamonds for a ring that I have been designing.  Natural pink diamonds can vary in intensity and it is important to colour match as closely as possible so that there is not a patchwork effect created for the finished piece. I can not imagine what it would be like to be colour blind…I almost feel like I have an over developed sense of colour…as I can be obsessed by matching and hate to see an uneven finish.

Striking the balance: gem stone colour grader

A client brought me her engagement ring which had been purchased many years earlier and was not the whitest of solitaires.  Her husband really wants her to wear the stone, however she would like a wider more impressive ring to be worn on her ring finger without a second band….so starting with a 6mm diamond….I start to draw and think…..I like the idea of arms hugging the diamond as it is such a sentimental stone and using soft pink diamonds makes her diamond look more white….these pictures are taken with my phone as I start to work and originally were not intended for the blog….The circle is the 6mm which is the size of the diamond and the 1.8mm diamonds are all laid out upside down….hence not that sparkly….As you can see it is not  perfect as there are gaps….so the next stage is to select 1.9mm stones and 2 x 2mm to make sure there are no gaps…I will use 1.8mm down the band….possibly tapering down to 1.7mm.  This client wants the ring to be generous with stones.

If you wear rings with a large stones you will know that they drop from one side of your finger to the other….we will set stones about ¾ of the way around the shank so that you will always see diamonds when the ring moves.

The ring must have balance and as the widest point will be about 10mm the double band will then be about 6mm with a gap of 2mm between it….We have chosen a micro pave setting style which will minimise the metal.  With pink stones I would usually recommend rose gold to enhance their colour…however my client is adamant that she wants white gold….so it is up to me

Trial and error: gem stones rearranged

to make sure the stones are not dominated by white gold and lose their colour…the micro pave style should ensure this….now it is up to the maker….and I will post the finished picture in a few weeks!

The main contender: don’t be fooled, the gem stone chooses you

Contender 1: paraiba tourmaline

I had such a compliment paid to me when I went stone buying yesterday….In my view the best coloured-stone dealer in London said I was different to every other jeweller….and he deals with some pretty impressive brands/names…..He said I always work from the point of view of the stone.  I have thought about this and he is right….I choose a selection of stones for every client and instinctively I often can guess which one they will choose….I almost feel when I am finding the right jewel for them that I can easily choose the obvious options and then there is a slightly off-spec stone which leaps out at me and I just have to bring home….and often that is the one they LOVE…..

Contender 2: natural faceted chrysoberyl

Gems have real personalities and I feel the stone picks its owner….odd I know and I promise I am no out-there hippie when it comes to this…..but it is weird how people respond when presented with a truly amazing array to choose from….One 18 year old girl had 17 different coloured sapphires and had chosen her one within 30 min……I can promise you not every client is that quick…but people just know when it is the right one…..very important for me that we get this right as every piece is an absolute one-off commission and not part of stock to be returned to a shop window.

Contender 3: purple spinel

I really enjoy teaching people about different types of gems and why they may admire different features of the stones and I suppose this is where the blog idea came from….clients suggesting I do webinars….too scary for me…..I can’t even have my photo taken for my website.  I’m building up to that one!

As I’ve handled so many stones throughout the year…I often have a favourite that I am hankering over…..For several years it was a cocktail ring with a large 15ct+ emerald-cut perfectly clear watermelon tourmaline…….pictured in my last blog….but now I am pretty sure I will be purchasing a birthday gift from my husband for myself….cheeky I know…I’m now getting excited every time I go to Hatton Garden as I am secretly shopping for my next special stone….This is something I will add to the blog each week if there is a new contendor in the running but I’ve included the first three above, so let me know what you think in the comment section below….

Showing their true colours: the schozophrenic nature of gem stones

As I have been bleating on about colours in stones and how they change with the light source, I thought it may be a good time to talk about some really special and rare examples of this.

Split personalities: dichroic gem stones

The photo I used in the last blog showed a sapphire which when moved changed from being blue to yellow, depending on the angle that you held it at….but that was all in the same light.  This is called pleochroism and occurs when light entering a stone is split into two separate pathways which are polarised at right angles to each other. As the light is travelling at different speeds through the pathways you can see different colours…..remember we talked in my last blog about how a stone absorbs light to create the colour it displays….well if the light passing through the stone is split into two it is called dichroic, and three is called trichroic.  Really technical all this….I can tell you loads more…but fear boredom creeping in….ask any questions below if interested in more?

It takes two: the bi-colour, watermelon tourmaline

As well as sapphires, tourmalines are famous for having many colour combinations displayed on the same stone, but they also have stones which are segmented across in a really clear line, like it has been coloured in.  They are called bi-colour watermelon tourmalines when they are a pink/green combination, but this can also appear in a blue/green.  On the Sassalina website I have a photo of a pink sapphire with two rough cut slabs of watermelon tourmaline which show concentric colour rings to great effect and also make a really modern and funky piece.

I won’t go into any more facts/figures about tourmalines for now but will share and some of my favourite examples…. 90 % of the time people just buy a stone because they love how it looks, or how the stone makes them feel….one of my clients said to me this week that her sapphire keeps her calm….how great is that? We all probably need a stone that does that for us at one time or other.

In the pink: red rubelite through to pink tourmaline

However, what is interesting is how the behaviour of the colour of a tourmaline can dictate its name.  Rubellite is an intense red tourmaline, however it must stay this colour in artificial light as well as daylight and if it does not, it is called a pink/shocking pink tourmaline. I mentioned before that some gems are so special and they never leave my memory….one amazing vibrant purple/pink tourmaline of about 10carats went off to live in Hong Kong with a Russian client of mine and I really wish I had held onto that one!

Reflecting on the spectrum of colours in gems can be very absorbing

Hi there, hope there is more than one follower now otherwise this will be a very personal education….perhaps you could fire over questions and I’ll answer them through future posts?

Complete spectrum: light absorption for precious stones

Anyway, I promised to talk about how stones have different elements of colour..First of all I need to explain how you can see the different colours of any jewel…..This is super-complex to explain…however, very basically, the colour of a gem depends on how it absorbs light. White light is made up of a spectrum of the colours of the rainbow. When light strikes a gem some spectral colours are absorbed and those that are not absorbed pass through or are reflected back, giving the gem its colour.  The way light performs is due to the individual crystalline structure of each stone.   In reality each gem has its own totally unique colour ‘fingerprint’…this is known as an absorption spectrum….which is visible through a special tool gemologists use called a spectroscope….what is amazing is that it looks like a bar code from the supermarket….obviously each stones’ spectrum has slightly different width black bands, however each type of gem…sapphire, emerald, topaz, garnet….has the same characteristics of absorption spectrum because each type of gem stone is made up of the same chemical compounds…

A thing of beauty: bi-colour sapphire

I hope this has not been too heavy going as it is no longer about the fun sparkly element of stones….but in a very practical way, when I show clients stones, I use different lamps in my house, I make them go outside, have a look at the stone at night and also I use a day light lamp which simulates the white light of the colour at midday….without fail all my clients are shocked at the variation in colour…..another unique quality and beauty to me of the coloured gemstone is that they are never static, they are always changing colour and reflecting light and catching the eye of a passer-by…..some are just sooo gorgeous they demand to be looked at…..

Colour in gemology certainly isn’t black and white…

With an amazing increased interest in yellow diamonds and an absolutely unprecedented uplift in the cost of diamonds over the last two years…I have noticed that my clients have become really open to yellow sapphires…the colour suits many skin tones…brunettes, redheads….and on a practical note my clients feel they can wear a yellow stone everyday with different fashion seasons and colours of clothing….

Sassalina design - yellow sapphire and white diamond ring

Last year alone I made three French lemon sapphire rings…we use the description ‘French lemon’ in a way to refer to the softer more natural colour of the genre.  Many stones are prized when they are quite a strong intense yellow…really to be close to the colour of a vivid canary yellow diamond, however my clients and I, so far, all favour the softer, more natural colour.  On my website and used as my avatar for Twitter is a gorgeous solitaire-cut, natural yellow sapphire (which came with a lab report to say there was no evidence of heating). There is also another 15ct stone with diamond surround, which is an amazing piece.  For the most recent ring, about to be photographed, we used a soft champagne coloured diamond to complement the colour.  Using combinations of colours is my greatest pleasure as this is really the creative part of what I do.

What is interesting about the yellow sapphire is that until the 19th century it was called an ‘oriental topaz’ and the green sapphire was known as ‘oriental peridot’. However, what is an incredible fact is that many sapphires that appear green actually consist of very fine alternating bands of blue and yellow sapphire, which can be visible under a microscope. The world of gems under a microscope is fascinating and I know is where I start to take on the white lab coated, beardy personality, however I would just love a few readers to become interested in what opportunity there is to learn from what became trapped or was alongside these natural stones when they were being formed millions/billions of years ago.

Finally, white sapphires….or the colourless variety….are relatively rare as it is corundum without any impurities (or metal oxides) such as iron and titanium for blue, vanadium for violet, small amount of iron for yellow and green, chromium for pink and iron and vanadium for orange.  As sapphires are hard stones they have a good lustre…something I will explain in another blog…but are basically sparkly….they are often for their own beauty..or to simulate diamonds….in order to make jewellery at a more affordable price.

JADA Fine Jewellery - white sapphire bangle

Jada Fine Jewelleryoften uses diamonds in the beautiful designs, however designer, Ceyda, recently showed me a bangle, which is being launched at Paris Vendome Luxury show, that has a single gorgeous white sapphire as its main gem….

Often sapphires have different areas of different colour in the stone and the way the cutter chooses to orient the stone dictates the colour you see….. a tale for my next blog….

Some like it hot: improving intensity of precious stones through heat treatment

At the end of the last post I really felt unhappy that I had not shown you a picture of the padparadscha (this word is Sinhalese for ‘lotus flower’)….In the flesh it is truly the most original and exciting colour, but it lends to moving on to talk about the orange/yellow sapphires as a comparison quite well…It is also important as it is the only variety of corundum that is given its own name, rather than being referred to a sapphire of a certain colour….so here it is….

When blogging about coloured stones, I think I should mention how the colour affects the price and value of a stone, as you can see the padparadscha is quite a subtle colour compared with other orange stones, this is one of the ways in which it is unique. However, interestingly stones are often prized on being a strong or vivid colour…Most noticeably coloured diamonds are actually categorized with the word ‘vivid’ to explain the level of quality of the stone’s colour.

All change: heat-treated rubies change from blue to red

There are ways to improve or make more intense the colour of a gem. This occurs most commonly by heating the stone. (Sapphires, for example, are heated at 1700-1800C).  This is an extremely common practice in sapphires, rubies and emeralds…so common that it is not a requirement of the stone seller to say that this process has taken place.  If asked the seller must disclose any treatment they know of, however they may be unsure and sometimes it is impossible to know.  Very important stones are sent to gem lab’s, like the one which used to be at Gem-A in Hatton Garden, to have a report prepared to say if there is any evidence of heating. Any changes which occur during heating create a permanent change.

I have talked about my lilac sapphire before, which is quite a soft colour and one of the ways I know it is a natural colour is that there is a rod of rutile in the stone. This would have fractured into parts along the rod had the stone been heated.  Lab’s look for this type of change in order to say if a stone has been treated, however many inclusions essentially disappear through heating and therefore do not leave any history.  When inclusions become less obvious the stone has better clarity and often better colour and therefore the stone becomes more valuable, which is why it is such a common practice.  I will talk about this from time to time as stones can change colour completely through heating….some of which you have probably owned or worn and never known that the stone originally started out completely differently.

Fashion in jewellery can make heat treatment a very important process when particular colours become a trend in the industry. I will talk about this in more detail in the next post.

In at nine: corundum and its sapphire and ruby offspring

Colour spectrum: corundum

Well, I start my second blog with the surprising knowledge that I have a follower….I don’t know who you are…but I really appreciate knowing that I am not just writing to the ether….I did promise you that I would talk about corundum and, as I now have someone reading, I don’t want to let down…here it is.

Corundum is a 9 on Mohs scale and therefore the second hardest material after diamond….very useful for making great rings that can be worn everyday and therefore a material I seem to use often. What is not commonly known is that rubies and sapphires are both termed corundum because they are principally made from aluminium oxide…When red, the stones are known as rubies, with the remainder being named sapphires.

Rubies vary from pinkish to purplish or brownish red, depending on the chromium or iron content of the stone. What is interesting is that aluminium oxide, with very small amounts of chromium, creates pure pink sapphires…as the chromium level increases you move towards rubies…however with just the right level of chromium and a tiny bit of iron the really beautiful and very rare

Rare beauty: the pink sapphire

pink/orange stone is formed. If there is also some titanium a purplish stone is created.

For me this is the most wonderful aspect of what I do…coloured gemstones should not come to order in the way that some retail jewellers present stock…I love the individual beauty and personal aspect to choosing a stone because it is just the right colour for you. Six plus years of going through the same process…it feels as though the stone chooses the wearer.

I admire stones almost every day of my life and some never leave my memory….There are so many varieties and colours to choose from, which makes it difficult to pick out an example that I personally love, however, one was an amazing 14ct lilac sapphire that I managed to keep. Like last week…if you check out my website you can see a lovely photo of the gem…it is the only lilac coloured one….next time I will chat about white, green and yellow sapphires…I wonder which will be you fav choice?

Mohs scale: the hard and soft side of gems

Under the loupe: Mohs scale

Another year….ano​ther person decides to start a blog….le​t’s hope my words are of interest to some gem lovers out there. My ambition is to share my gem knowledge without making you think of a bearded man in a white lab coat!

There are so many amazing types of precious gems, however the reason why the general populations tend to restrict themselves to wearing diamonds, blue sapphires, rubies and emeralds is primarily because of how hard wearing they are.

On the whole the industry uses Mohs scale of hardness to determine the durability of stone from the effects of wear and tear. I thought I would start with explaining this so when I rabbit on about how hard a stone is you will have a scale to visualise….Obviously the scale below shows only one gem example for each level….

Put really simply….air contains particles of crushed quartz…weird idea hey?….anyway as quartz sits at 7 on the scale….gemmologists generally consider stones harder than 7 to be robust against being ‘rubbed’ by the crushed quartz particles….of course people do have jewellery made from lots of stones lower down the scale, i.e. fluorite, however they would be expected to show signs of wear earlier than harder stones. In a future post I will look at brittle stones…

Here comes the science part: Moh scale in detail

The second representation of the scale shows how there is a greater difference in hardness between a diamond (10) and corundum (9), than corundum (9) and talc (1) By the way corundum is the group name for rubies and sapphires….I will explain more about why in my next post….