Using the right gemstone can really add that special touch to a piece of jewellery but when you are just getting started, choosing which gemstones to use can be a little scary.
That is why I have created this short guide, to help you get started in the wonderful world of gemstones.
When looking for information about gemstones, you will commonly see their hardness mentioned such as 10 for Diamond or 8 for Topaz but this is only one of three factors that make up gemstones durability, a breakdown of the three are:
- Hardness – this is how hard the surface of the gemstone is and the reference point for hardness is the Mohs scale, that runs from 1 (Talc) through to 10 (Diamond). The harder the stone, the better its ability to resist scratching and abrasion.
- Toughness – this is the internal strength of the stone, how well it can resist fracturing (non-directional breakage) and cleavage (directional breakage). Unlike hardness, there is no recognised scale for this but it generally ranges from poor (Tanzanite, Emerald) to excellent (Jade).
- Stability – this is the ability to resist both physical (heat, light) and chemical (exposure to acids) changes. As with toughness, there is no recognised scale for this but it range from poor (Opal, Pearl) to excellent (Diamond).
Learning more about gemstone durability will make working with gemstones much easier and I will give a couple of examples below.
#1 Soldering and Pickling
Stone setting is usually done once all of the metalwork is finished, this is because it prevents the stone from being accidentally damaged. But there are times when a piece needs to be soldered and pickled when the stone is in place, such as repairs.
And this is where stability comes in to play as being exposed to the heat of a jewellers torch and/or being placed in a pickling solution can seriously damage the stone and this damage is often irreversible. In most cases the best option is to remove the stone before doing any soldering.
Care should be taken when soldering with even very stable gemstones such as Diamonds still in the setting as without some form of heat protection, the surface of the Diamond can oxidise.
#2 Stone Setting
For lots of jewellers, stone setting is one of the scariest things to do as they are worried about breaking the stone. And as someone who does setting myself, I completely understand but knowing a little about the stone you are setting can make the process a little less stressful.
This is because when you know what the hardness and toughness of the stone is, you can adapt your setting style.
For example, with soft and more brittle stones such as Peridot or Opal, you have to be more careful and not to apply too much pressure on the stone, instead a slow and steady approach with lots of small adjustments, ideally using brass rather than steel tools is generally the best way to go.
With harder and tougher stones such as Diamond or Sapphire, you can apply more pressure on the stone, although care does still have to be taken. They can also be a little more forgiving if you slip as the stones are generally harder than the metal the tool is made of.
#3 Finishing and Polishing
The final part of the jewellery making process is finishing and polishing and it is possible to damage the stone at this point, so care needs to be taken, especially when cleaning up the setting.
This is because abrasives, such as sand paper and rubber wheels can damage softer stones, harder stones such as Diamonds, Rubies and Sapphires are usually ok.
But on softer stones, these abrasives can take the finish off the stones and may leave a dull finish or if not careful or the complete removal of a facet from a stone (I learnt that one the hard way!). Ideally, you want to use an abrasive that is softer than the stone.
A similar issue can be found if you are using a very aggressive polishing compound as it can affect the surface of the gemstone. Once the gem is set, you don’t really want to use anything more aggressive than pre-polish (Tripoli, Luxi Blue etc) and then your finishing polish.
Once you have finished polishing, it is time to get the piece clean and sparkly but once again, care needs to be taken when doing this as Ultrasonics and Steam Cleaners aren’t suitable for all types of gemstones.
For example, with brittle stones such as Emeralds and Tanzanite, the ultrasonic waves can in some cases cause the stone to break, another side effect with Emeralds is that they are often fracture filled with oils that can be removed by the ultrasonic cleaner.
It is a similar story for steam cleaners and that is why both should only be used with durable gemstones such as Diamonds and Sapphires.
The best option in most cases is the classic, warm water, a small amount of washing up liquid, a soft bristled brush and a big of elbow grease.
The Right Stone for the Job
Knowing how to work with different kind of gemstones when you are making jewellery can also translate to choosing the right stone for a piece of jewellery you are doing for yourself or a commission for a customer.
Ring, Earrings or Pendant?
If you have to take more care of the stone when it is with you at the bench, there is a good chance that the gemstone isn’t really suitable for use in a ring.
Emeralds, Tanzanite and Opals are a great examples of this as they have to be treated with a lot of care due to not being very durable gemstones and this generally means that being worn in a ring, especially one that is worn everyday isn’t going to do the stone much good.
Instead, they are better suited to being used in a pendant or pair of earrings as their life is going to be much easier, with less chance of the stone getting broken or damaged.
For everyday rings such as engagement rings, a stone that is durable is going to be a much better option and is one of the reasons why Diamonds are such a great choice.
If you have a customer who is wants to use a soft stone in an everyday ring, talking through and explaining the reasons why it is not the best option can save a lot of time, hassle and in some cases heartache (on both sides).
Knowing how durable a gemstone is, can have a big influence on the type of setting that you are going to use as different styles of settings will give different levels of protection.
This is also useful if the customer is adamant of having a gemstone in a ring, that is not particularly durable.
For softer and more brittle gemstones, a rub over or bezel setting is often the best option. This is because not only does the setting provide more protection for the stone but the setting process can be more gentle.
If the gemstone is more durable, then more exposed settings such as claw or prong settings can be a great option as they don’t require as much protection from day to day knocks and bangs.
But How do I learn About This?
To learn lots about this, requires studying to become a gemmologist, like myself but if you don’t want to do this, there are some great books out there that you can use as reference guides at the bench.
One of these is the Working With Gemstones, A Bench Jeweller’s Guide By Arthur Anton Skuratowicz And Julie Nash, that is available from Cooksongold. I looked through this book when I doing the demonstration days last year and it contains lots of practical information about lots of different gemstones.
Definitely worth adding to your collection.