Colourless Gemstones in 18th to 19th Century Portuguese Jewellery
From a gemmological point of view, the jewellery production of the second half of the 18th century and first quarter of the 19th century in Portugal differ from the European production where coloured or colourless pastes, or glass, were rather abundant. High-end jewellery artefacts all around Europe, and in Portugal for all that matter, were, of course, embellished by the most valuable gems of the period, namely diamonds, pearls, rubies, emeralds and sapphires. On this higher jewellery segment, differences between Portuguese and European jewellery were negligible in terms of the gems that were used. The main difference lies on jewellery artefacts of a lesser value, mostly made in silver, where the use of the then almost new coloured gemstones is significant.
An historical circumstance is behind this since up until 1822 Brazil was a Portuguese colony. Even the capital of the Portuguese empire after the Napoleonic invasions of 1807, when prince regent João (the future king João VI) became Rio de Janeiro when the nation was known as the United Kingdom of Portugal, Brazil and the Algarves. This close relationship positioned Portugal on a privileged trade situation receiving shipments of Brazilian gems and gold discovered in the late 1600s in Minas Gerais. This discovery brought many adventures to the area in the search for the precious metal and that eventually resulted in the discovery of more gold and new gem occurrences, the most important of which was diamond in the early-1720s. Among the other local gems varieties with significance in this period, the following stand out: topaz (colourless, yellow, orange and pink, including the so-called “imperial” colours), quartz (mostly rock-crystal and amethyst), chrysoberyl (yellowish-green to greenish-yellow) and beryl (specially aquamarine and near-colourless varieties). It is undeniable that these Brazilian gems, so conveniently available in large quantities to Portuguese jewellers, played a fundamental role in Portuguese manufacturing leaving a truly typical signature to it, quite different from the European jewellery of the same period, as it has been stated before.
In this blog post only colourless gems will be addressed and contextualised in the jewellery designs as well as the types of setting, foiling and other appearance modification techniques used in Portugal in the 18th century to the early 19th century. Note that the variety of colourless gem materials available in jewellery is not that comprehensive. The contrary can be said it one sees them as collectors' stones as in the late David Kent’s FGA collection of colourless gemsstones (see The Journal of Gemmology (1987), vol. 20, no. 6, pp. 344-345), but is interesting to understand how and why these were used. From a practical gemmological stand point, the use of classic gem testing techniques and some observation skills can almost always positively distinguish between these colourless gems used in Portuguese jewellery of this period.
Diamond
Due to the considerably large amounts of Brazilian diamonds being produced after their discovery in the 1720s, diamonds became the most relevant gem material in 18th century jewellery not only in Portugal, but also all around Europe. It is not too much to remember that until then, diamonds came essentially from India and in smaller quantities from Borneo (in today’s Indonesia) serving jewellery makers in Europe and in the Orient. To put this in perspective, on those days when Indian production was at about a few thousands of carats a year, according to published statistics (that do not consider smuggling, contraband and non-declared goods), the yearly production in Brazil was reportedly ten times larger during some periods of the 1700s. This massive availability caused a significant impact in jewellery design, in cutting, in fashion and, of course, in demand. Regardless to say that this yearly production would be negligible today, as the world diamond production is measured not in tens of thousands of carats, but in millions of carats (according to official Kimberley Process figures, in 2018 the production was about 148.4 million carats in volume - Brazilian exports were 250,940.42 carats, a mere 0.17% of the world diamond production). But 300 years ago the use of diamond-set jewellery was a privilege of very few among the most powerful and wealthy figures of society, so the many tens of thousands of carats were enough to satisfy that selected clientele.
Coincidently, almost at the same time the fashion trends in term of cutting styles were changing with an increase in the popularity of the so-called triple cuts, with three sets of facets in the crown (the upper part of the cut), that was known as the brilliant cut. Notwithstanding the fact that this style of cut was already known in the late 17th century, its popularity was only confirmed in the mid-1700s and the then popular rose cuts, used since the 1400s, began to decline in demand, specially for the larger goods coming from Brazil in larger numbers. The Candle lights of the lavish ballrooms and salons of the exquisite social events of the period caused a greater visual impact on the brilliant cut when compared with the rose cut. The name of the cut, brilliant, speaks for it self on this matter.
Devant de corsage, ca. 1758, featuring diamonds, rubies, garnets and a foiled topaz. Photo © Carlos Pombo Monteiro, Fundação Eugénio de Almeida/Arquidiocese de Évora
On Portuguese jewellery in particular, the impact of a larger diamond availability is clearly seen in the way jewels were designed. Before the large influx of Brazilian diamonds, jewels were mostly art pieces made in gold or silver by highly skilled goldsmiths with a great deal of handcraft experience in working the metal. Since gems were scarce, only but a few diamonds were set; after the influx of Brazilian stones, the entire artefact became fully covered by stones with the noble metal, mostly silver, being a mere holder for all those stones and becoming secondary in importance. Gemstone setters were busy as ever and their skills were in high demand. In other words, jewels became a whole new thing, from precious metal almost sculptures to gemstone-set decorations. The evolution of these designs and taste can be testified by the increasing number of diamonds and the decreasing artistic metal craftsmanship present in jewellery during a few decades period in the mid to late-1700s . It is also noticeable that rose cuts are much more abundant in pre mid-18th century pieces that in the later half a century.
Curiously however, although the then new brilliant cut offered a greater amount of light return, when compared with the rose cuts, the settings used were closed, sometimes darkened, concealing the pavilion, a traditional fashion used for centuries (opened settings, sometimes called “à jour”, became fashionable only in the 1800s). The brilliant cut diamonds in these closed, sometimes darkened, settings created a visual effect in the cullet, making it look black. The dark interior of the closed bezel setting could be seen only through the culet. This dark cullet effect could not be achieved by the common diamond simulants of the period, specially when set with the then-traditional reflective foil backs. We’ll come back to this further bellow.
Order of the Three military Orders featuring old cut diamonds, rubies and emeralds. Royal Treasure Museum, Palácio Nacional da Ajuda, Lisboa
All in all, diamonds were indeed extensively used due to their greater availability accompanied by a momentary price drop in the first years of Brazilian production. Jewellery designs were no longer dominated by artistic metal craft but by rather by the stones that totally covered the piece. The Portuguese Crown Jewels, especially the late-1700s artefacts, are very good examples of this where fine and large stones can be seen decorating the state and military insignia of the period’s Portuguese Royalty, where metal is barely visible only in the settings.
Colourless Topaz
Being diamond the most significant colourless to near-colourless gemstone on this period, other gems came into play in jewellery. As said, the abundance of diamonds created a new way of designing jewels with an immense profusion of stones over an almost invisible metal structure. This style became a fashion trend and in high demand even when using other gemstones.
The search for gold and diamonds in the early 1700s brought many adventurers and explores to the Minas Gerais area, and looking at the ground, specially in fluvial-associated sediments, eventually revealed other gemstones that would become relevant. Due to its significant alluvial occurrences and its specific gravity (topaz SG = 3.53, diamond SG = 3.52), topaz might have been collected along with diamonds. It was not difficult, however, for the experienced dealer and cutter to separate between the two, namely for their different external crystal or pebble shapes, lustre, external marks and hardness, of course. It was realised that this gem material had jewellery potential as it had been proven in the past elsewhere in central Europe, namely to simulate (not deceivingly) diamonds in silver jewellery. Before the discovery of the techniques of treating colourless topaz into the popular vibrant blues so fashionable in today’s markets, colourless topaz was used as it came out and was quite fashionable in Portugal.
© Museu Nacional de Arte Antiga
The style of cut of such stones was very close to the so-called double and triple cuts used for diamonds, always with a significant culet size. The settings were usually made in silver and were closed but, contrarily to the diamond's close settings, the backing was not dark but rather a reflective foil, supposedly to enhance the stone’s brilliance. It happens that, in such circumstances, the culet would appear dull or white and that was not the visual aspect that became so popular due to the visual appearance of set diamonds where the closed settings and darkened back caused the culet to appear black. To achieve that effect with topaz, and for any other stone rather than diamond, setters used a subterfuge by painting a black dot in the culet itself, creating that same illusion. A closer look into non-diamond foil-backed colourless gemstone jewellery artefacts from Portugal made in this period shows the presence of black dots in almost every stone’s cullet. All are painted dots as it can be seen under magnification (see image bellow).
Some regional trade names, like “minas novas” and “pingo d’água” were used for topaz on those days, especially in the beginning of the 19th century. Minas Novas is actually a region in Minas Gerais from where white topaz reportedly came in significant quantities in the early 1800s. The lack of gemmological knowledge and verbal tradition among traders and consumers led to the indiscriminate use of this trade name for the other two Brazilian colourless gem varieties extensively used in Portuguese jewellery this period: quartz and beryl. This has caused some confusion in the interpretation of the actual gem content of 19th century items, as well as in some 18th century jewels where some dealers still call anachronistically “minas novas” to every non-diamond colourless gem material set in Portuguese jewellery.
in the photo: a painted culet. Note the outline of the culet facet and the paint mark © Rui Galopim de Carvalho
Colourless Quartz
What was mentioned earlier for topaz applies here to quartz when in comes to colourless quartz also known as hyaline quartz or rock crystal (in the gem and jewellery trade). A significant difference lies in their relative quantities with quartz much more abundant that topaz. It was soon understood that the tips of quartz crystals and their eroded alluvial parents were suitable for faceting, much in the same way as European and Asian colourless quartz were in the past for both faceting and carving. The use of faceted rock crystal in 18th century silver jewellery is extensive using the same closed settings, reflective foil backs and the black painted culets as mentioned for colourless topaz. It is noticeable, though, that the finishing quality of the jewellery pieces using quartz is not as delicate as those using topaz, specially in civil or profane pieces, indicating an interesting rarity factor and a different value perception between both gem varieties, with topaz being more exclusive and possibly expensive. The lesser hardness of quartz (7 in the Mohs scale, compared with 8 for topaz) and its lower reflective properties do make them less brilliant than topaz and, hence, probably less desirable as a faceted stone. The fact that it was much more abundant may have also played a role here.
The separation between quartz and topaz, however, is hard to achieve by visual observation alone.
Silver and foiled rock-crystal earrings © Carlos Pombo Monteiro, Fundação Eugénio de Almeida/Arquidiocese de Évora
Beryl
Again, what was said for topaz and quartz in terms of the way they were set and used in jewellery also applies to colourless beryl. In fact, the vast majority of beryls identified in Portuguese jewellery are not colourless but rather near-colourless, almost always with a very light greenish-blue tint, meaning that they are, in fact, very light aquamarines. Beryl rarely occurs in the true colourless variety, known as goshenite. Like with quartz and topaz, a closed setting is used with a reflective foil in the back, as well as with the so mentioned black dot in the culet to create the desired “diamond dark culet” effect. So visually, at first glance, all these colourless gemstones are alike. A subtle difference, however, between these gems is the face up higher brilliant appearance of beryl and, as with topaz, these were used in finer pieces when compared with rock crystal.
Plaque of the Order of Nossa Senhora da Conceição de Vila Viçosa set with near-colourless beryls and topaz © Carlos Pombo Monteiro, Fundação Eugénio de Almeida/Arquidiocese de Évora
In conclusion, the exploration of the Brazilian soil in the 18th and 19th centuries lead to the discovery of several gem materials, mostly diamonds, that made a strong impact in the whole concept of jewellery, not only in Portugal, but also in Europe. Among the colourless gem varieties, topaz, quartz and beryl also secured a place among the choices of those days’ Portuguese jewellers being used, set and fashioned in a very typical fashion in silver artefacts of a much lower cost that diamond jewellery. Many of those pieces survived due to the lower values associated with both the gems and the metal, as a different fate was met for diamond set and/or gold made pieces for obvious liquidity reasons. Several public and private museums have numerous profane and devotional artefacts featuring these Brazilian colourless to near-colourless gemstones that are valuable testimonies of the period’s jewellery production and are the delight for historians, collectors and passionate professionals or consumers.
Edited and extended from Galopim de Carvalho, Rui (2008), Colourless gems in Portuguese 18th to 19th century Jewellery, Gems & Jewellery News, Vol. 17, no. 1, pp. 25-27. Feature cover photo © Carlos Pombo Monteiro, Fundação Eugénio de Almeida/Arquidiocese de Évora