Inside Look: Gemstone Sourcing

| 5 min read

Here at Gemporia, we're often asked how we go about buying our gemstones, and how we make sure that you always get the best deals. So, here's how we do it!

To begin, it's important to note that there are a few elements in our gemstone-buying process that always stay the same. Firstly, regardless of the country you're in or what gemstone you're buying, business transactions are always completed using American dollars.

As well as this, every single gem parcel we buy is sent to a government-managed gem laboratory for testing - even if we buy the rough directly from the mine itself. We do this for a few reasons:

  1. Although mistakes are rare, it's possible to end up with gemstones that are not the same as was disclosed by the seller

  2. Miners can accidentally mis-identify gemstones that come from the same place - for example, it's hard to tell the difference between a rough Spinel and a rough Ruby

  3. We're able to give a lifetime guarantee that all the gems we sell are genuine, and as stated on the authenticity card that you receive with your piece of jewellery

Realistically, these are the only parts of our gemstone-buying process that stay the same! From here, everything else changes depends on the gemstone, the country and whether we're buying stones that are already cut, as opposed to buying rough that we will cut ourselves.


Sourcing gemstones at the recent Hong Kong Gem Show

First, it's important to note that we always refer to gemstones as parcels, regardless of whether we're buying a few carats or tens of thousands.

Parcels of gems are normally divided by type, shape and size. If we're buying gems that are already cut and polished, we usually evaluate all the parcels first before offering an average price per carat for the deal. In the gemstone trade, deals are always negotiated by arriving at an average price per carat that a buyer is prepared to pay, and a seller is prepared to accept.

This is where it's easy to understand why most cutting houses try to maximise the carat weight they can produce from a rough.

Alongside this, what we also try to do is agree on a percentage of the parcel that we can return after our experts have tested it. Then, once we've decided which gemstones we're buying and which we're returning to the supplier, it's time to grade them.


Once bought, all gemstones must be properly graded

At this stage in the process, the supplier will have already divided the gemstone parcel by size and shape; if it's a large purchase, they may have further separated them by depth of tone. To simplify this, here's an example:

Let's say we're looking at a 6x4mm parcel of oval-cut Tanzanites, and that there are 80 pieces in total. Ideally, you would not have to further divide the parcel, because the bigger the parcel, the more flexibility the jewellery designer gets in terms of how many pieces they can produce.

However, the parcels usually get divided again into many smaller sub-parcels, in an attempt to create only the finest jewellery. So, it's not uncommon to see parcels divided a further 10 or 15 times, due to differing shades and clarities in gemstones. Granted, this can be a frustrating part of the process - but it's done in an attempt to create only the finest jewellery, so we consider it necessary.


Once all our gemstones are graded, they must be correctly and fairly priced

At this point in the process, the individual details of each sub parcel are entered into our database. In this database, we include:

  • Quantity
  • Size
  • Carat weight
  • Tone
  • Saturation
  • Clarity

From there, we allocate the cost price, which is a lot more challenging than it sounds!

For context, let's imagine that, for the 80 pieces of Tanzanite we referred to earlier, we paid $30 per piece. We then divide this parcel further into three sub parcels: one with a deep tone, one with a medium tone and one with a lighter tone. But, rather than entering them all into the system at $30, we will add a different value to each bag.

As long as the sum of each bag ends up at the same total value, everything is correctly balanced.


Finally, the designers can choose which gemstones are best for their jewellery

As one of the final points in the process, the designers now gain access to the database to choose which stones will be used in each jewellery piece. For example, if the designer decides to make a trilogy ring with the gems in one of the sub parcels, the gemstone sorting team will go through the parcel once more to find which three stones are the closest match.

This process is simply called 'colour matching', but there's much more to it than that; the gem sorters has to evaluate the gemstones' surfaces, lustres, clarities, tones and saturations. To the untrained eye, the stones may look identical - so choosing the right stones for each piece requires extreme analysis and skill.

Once completed, the gems are bagged individually and sent to the workshops, where they're intricately set into a beautiful piece of jewellery.

We hope this has given you a unique insight into the way we source our gemstones, and taught you a little bit about how we make sure you not only get the best quality jewellery, but also at the best price.

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