GEMSTONES, SEMI-PRECIOUS STONES, OR PRECIOUS STONES?
They are beautiful, colourful, shiny and expensive. They were dazzling the world ten thousand years ago, and today is no different. For a mineral to be classified under the precious stone category, several criteria need to be met. A precious stone needs to be liked, have a great shine, fine colour, translucency and hardness. Today, meeting only one of those criteria is enough for a stone to be classified as precious. However, this has not always been the case. Together, let’s take a look into the history of semi-precious stones, gemstones, and precious stones.
In the past, only very expensive stones were classified as gemstones, while you could find very common stones in the semi-precious category. Grouping stones as gemstones, precious stones, or semi-precious stones only really began at the beginning of the 19th century.
Semi-precious stones
Until 1935, semi-precious stones were considered those minerals that did not meet at least one of the criteria, which decided whether the minerals categorise as either gemstones or semi-precious stones. A few of those criteria regarded the clarity, hardness, or the stone’s ability to be cut.
Did you know that…
…high-quality semi-precious stone could have had a higher price than a poor-quality gemstone?
These stones were once categorised as semi-precious:
- Quartz (different colours)
- Garnet (red and green)
- Turquoise
- Topaz (yellow)
- Nephrite (green and white)
- Tourmaline (pink, green, and black)
- Zircon (red, orange)
Since 1935, the only minerals to be considered gemstones, were clear ones, with the ability to be cut, and that scored 8 or higher on the Mohs hardness scale. Other stones, regardless of whether they were meeting all the criteria, if scoring lower than 8 on the Mohs hardness scale, were categorised as a semi-precious stone. The paradox of this lies within the Emerald, that based on these conditions should also be categorised as a semi-precious stone. His hardness moves around 7.5 and 8 on the Mohs scale, and despite this, Emerald has been historically viewed as one of the most valuable gemstones, along with the diamond, sapphire and ruby, which together form the ‘top precious stones’.
Precious Stones
For these inaccuracies and overlaps, the term semi-precious stones were abandoned in 1935, with the issuing of new binding nomenclature of stones by the international organisation BIBOA (Bureau International des Associations de Fabricants, Grossistes et Détaillants de Joaillerie, Bijouterie, Orfévrerie et Argentiere, residing in the Hague). A compromise has been made by introducing a new term ‘gem (precious) stone. Since then, that is how the rest of the minerals, clear and unclear, which are used for jewel manufacturing, are categorised.
So, what can be considered a precious stone? According to the definition given by the International Jewellery Confederation CIBJO, which also publishes lists of approved precious stones that are “natural inorganic materials with the exception of metals used in jewels and other artefacts”. This regards over 100 natural materials (minerals or rocks), which meet the optic criteria and physical properties (colour, clarity, shine, shape etc.), have a specific endurance and are appropriate to be used in jewellery, and of course, they also have its own value. This is, however, significantly dependent on current fashion trends and other factors.
Five categories of precious stones
Overall, we can separate precious stones in five different categories:
1. Main precious stones, like a diamond, corundum (sapphire, ruby), beryl (like a variety of emerald or aquamarine), topaz, garnet, opal, tourmaline etc.
2.Secondary, like pearls, quartz and its varieties, amber, turquoise
3. General, for example, chalcedony, agate, nephrite, jade, or feldspar
4. Rare, which are not usually used for the same purposes, such as andalusite, anatase or rutile
5. Synthetic, which are made artificially
Gemstones can further be subcategorised as minerals (diamond, corundum, beryl, quartz, tourmaline, rubellite etc.), vegetals (amber), or fossils (pearls, nacre, sea coral, mussels…).
What and how to choose?
If you decide to invest in a jewel with a gemstone embedded in it, a great option is an antique one. The value of such a jewel will not only be established by the material used but also the handcraft behind it. Today, only a small number of people handcraft jewellery of such perfection and detail, compared to how old goldsmith masters could, especially when it comes to early diamond cuts.
Moreover, every antique jewel has hallmark originality and you won’t meet another person with the exact same piece. Thus, the value of such jewel really is hidden within the story that lies behind it.