Capital Assets: Coloured Stone Highlights from Bonhams’s London Jewels Auction

September 16, 2021

By Katerina Perez

6 min read

As someone who follows the pathways of remarkable gems at global auction houses, it is fair to say I have seen my share of enchanting and valuable jewels. Sometimes, though, a particular sale piques my interest, whether that’s because of a singular spellbinding piece or a run of unheated and untreated coloured gemstones. The upcoming London Jewels auction at Bonhams is one such attention-grabber! Here are some of my highlights from the sale, which is due to take place on 22nd September 2021.

Provenance is power in the auction world, which is why a brooch once worn by the Duchess of Devonshire is the conversation starter for Bonhams’ London Jewels auction on 22nd September 2021. The brooch itself is from the Belle Époque period, which dates from the late 19th century right through until the advent of World War One. It was owned by Deborah Cavendish, Duchess of Devonshire (1920-2014) and presumably made a splash at society events with its swimming pool hued aquamarines. There’s a large oval-shaped gem, set horizontally and bordered by old brilliant and single-cut diamonds, and a second detachable aquamarine drop that’s millegrain-set and rose-cut diamond capped for added pizazz. The entire thing is mounted in platinum and has a pre-sale estimate of £25,000 – 35,000.

This Belle Époque aquamarine and diamond brooch, circa 1905, was once owned by Deborah, Duchess of Devonshire, and is the star lot of the Bonhams London Jewels auction in September 2021

This Belle Époque aquamarine and diamond brooch, circa 1905, was once owned by Deborah, Duchess of Devonshire, and is the star lot of the Bonhams London Jewels auction in September 2021

 Belle Époque aquamarine and diamond brooch with a large, detachable aquamarine drop and a millegrain-set rose-cut diamond cap, mounted in platinum

Belle Époque aquamarine and diamond brooch with a large, detachable aquamarine drop and a millegrain-set rose-cut diamond cap, mounted in platinum

Those with knowledge of British aristocracy might know of Deborah, Duchess of Devonshire, as one of the six ‘Mitford sisters’, who hailed from an important family and “enthralled the public with their stylish – often controversial – lives, as well as their contrasting political views,” according to Bonhams. As always, I find myself thinking “if only this brooch could talk,” as the Duchess was often found conversing with playwrights, artists, politicians and even her childhood friend, John F. Kennedy, the 35th President of the United States.

An Art Deco aquamarine and diamond bracelet, circa 1930, featured in the Bonhams London Jewels auction of September 2021

An Art Deco aquamarine and diamond bracelet, circa 1930, featured in the Bonhams London Jewels auction of September 2021

Although this is the most storied of the pieces in Bonhams’ upcoming sale, there are plenty of attention-grabbing gems to be found elsewhere. Let’s start with an obvious competitor – a fancy coloured diamond ring by Boodles, set with a cushion-shaped natural fancy purplish pink diamond, weighing 2.52 carats, and an Ashoka-cut diamond, weighing 3.23 carats that’s D-colour and of VVS1 clarity. This ring has an estimate of £280,000 – 420,000.

An emerald cameo and diamond ring from the first half of the 20th century, featured in the Bonhams London Jewels auction of September 2021

An emerald cameo and diamond ring from the first half of the 20th century, featured in the Bonhams London Jewels auction of September 2021

 An emerald, sapphire and diamond brooch, circa 1925, featured in the Bonhams London Jewels auction of September 2021

An emerald, sapphire and diamond brooch, circa 1925, featured in the Bonhams London Jewels auction of September 2021

 An Art Deco coloured diamond and diamond picture bracelet, circa 1925-30, featured in the Bonhams London Jewels auction of September 2021

An Art Deco coloured diamond and diamond picture bracelet, circa 1925-30, featured in the Bonhams London Jewels auction of September 2021

 This Art Deco bracelet contains a 2.75 carat principal diamond set within a stylised skyscape of old brilliant-cut diamonds, marquise, pear and single-cut diamonds with a range of yellow, brown and blue tints

This Art Deco bracelet contains a 2.75 carat principal diamond set within a stylised skyscape of old brilliant-cut diamonds, marquise, pear and single-cut diamonds with a range of yellow, brown and blue tints

When you hear the word “Ashoka,” it often signifies that a fantastic diamond awaits you. Why? This modified cushion-cut with a rectangular shape and rounded corners must be fashioned from a particular (and more unusual) shape of rough diamond, meaning they’re rarer. According to Boodles, only one in 50 diamonds mined can be cut this way.

A cushion-shaped fancy purplish pink diamond, weighing 2.52 carats, set with a 3.23 carat Ashoka-cut diamond in a ring by Boodles, featured in the Bonhams London Jewels auction of September 2021

A cushion-shaped fancy purplish pink diamond, weighing 2.52 carats, set with a 3.23 carat Ashoka-cut diamond in a ring by Boodles, featured in the Bonhams London Jewels auction of September 2021

Bonhams goes on to explain: “The Ashoka-cut lends its name, and was inspired by, the original Ashoka Diamond – a 41.37 carat, D colour, flawless diamond – from the highly coveted Golconda mine in India. This original diamond was itself named after Ashoka the Great, who ruled in India during the 3rd century BC […] Based on the Ashoka Diamond, New York diamantaire, William Goldberg, developed and patented the Ashoka-cut in 2000, and Boodles are the only British jeweller to offer Ashoka-cut diamonds in their collection. The Ashoka-cut displays an additional five facets to the 57 facets of brilliant-cuts, requiring the rough diamond to be larger and longer than average, and it is known for its typically larger ‘spread’, enabling the polished diamond to appear larger when viewed face-up.”

A Belle Époque tiara with approximately 25 carats of old brilliant, oval, cushion and pear-cut diamonds, circa 1905, attributed to Giuseppe Knight, featured in the Bonhams London Jewels auction of September 2021

A Belle Époque tiara with approximately 25 carats of old brilliant, oval, cushion and pear-cut diamonds, circa 1905, attributed to Giuseppe Knight, featured in the Bonhams London Jewels auction of September 2021

Next, there is a cluster ring with an octagonal step-cut sapphire of 8.70 carats, surrounded by brilliant and marquise cut diamonds with a total weight of 2.30 carats. The sapphire contained herein is of Burmese origin with no indications of heat treatment, which undoubtedly contributes to its £60,000 – 80,000 estimate. Moving on to sapphire’s sister stone, ruby, we have a pair of Graff hoop earrings containing 20.65 carats of scarlet hued gems and 14.25 carats of colourless diamonds, estimated to sell for £40,000 – 60,000. According to their accompanying report, one ruby in this pair of earrings – a 1.42 carat gem – is of Burmese origin, although evidence of heat treatment can be observed. There’s also a beautiful 4.37 carat, natural colour oval-cut Burmese spinel up for auction, set between tapering baguette-cut diamond shoulders in a simple but effective ring design. This would certainly be high on my wish list! Pre-sale estimate: £12,000 – 18,000.

An 8.70 carat octagonal step-cut Burmese sapphire ring with brilliant and marquise-cut diamonds, featured in the Bonhams London Jewels auction of September 2021

An 8.70 carat octagonal step-cut Burmese sapphire ring with brilliant and marquise-cut diamonds, featured in the Bonhams London Jewels auction of September 2021

 A 4.37 carat oval-cut spinel ring with tapered baguette-cut diamond shoulders, featured in the Bonhams London Jewels auction of September 2021

A 4.37 carat oval-cut spinel ring with tapered baguette-cut diamond shoulders, featured in the Bonhams London Jewels auction of September 2021

 Graff hoop earrings with 20.65 carats of oval-cut rubies and 14.25 carats of diamonds, featured in the Bonhams London Jewels auction of September 2021

Graff hoop earrings with 20.65 carats of oval-cut rubies and 14.25 carats of diamonds, featured in the Bonhams London Jewels auction of September 2021

 Graff 17.30 carat fancy light yellow diamond ring with two pear-shaped diamonds, featured in the Bonhams London Jewels auction of September 2021

Graff 17.30 carat fancy light yellow diamond ring with two pear-shaped diamonds, featured in the Bonhams London Jewels auction of September 2021

 Zolotas choker/bracelet and ear-clip suite, circa 1972, crafted in the archaeological revival style, featured in the Bonhams London Jewels auction of September 2021

Zolotas choker/bracelet and ear-clip suite, circa 1972, crafted in the archaeological revival style, featured in the Bonhams London Jewels auction of September 2021

Finally, there are a further two pieces I want to draw your attention to: a Graff diamond ring and an Art Deco aquamarine bracelet. The former contains a cushion-shaped fancy light yellow diamond of 17.30 carats, surrounded by 1.66 carats of pear-shaped diamonds, and has an estimate of £120,000 – 150,000. The latter is dated to the 1930s and has octagonal plaques of bullet and shield-shaped aquamarines, alongside single-cut diamonds and further aquamarines set in platinum. Bonhams notes that the composition of this bracelet is comparable with the aquamarine jewellery of Cartier London, although this piece is not marked as such. This piece is estimated to sell for £10,000 – 15,000.

Grima pendant with a hexagonal polished amethyst ‘slice’ and diamonds, circa 1970, featured in the Bonhams London Jewels auction of September 2021

Grima pendant with a hexagonal polished amethyst ‘slice’ and diamonds, circa 1970, featured in the Bonhams London Jewels auction of September 2021

 Charles De Temple ‘Wrapped’ cultured pearl necklace, circa 1970, featured in the Bonhams London Jewels auction of September 2021

Charles De Temple ‘Wrapped’ cultured pearl necklace, circa 1970, featured in the Bonhams London Jewels auction of September 2021

 Sapphire and diamond pendant earrings, featured in the Bonhams London Jewels auction of September 2021

Sapphire and diamond pendant earrings, featured in the Bonhams London Jewels auction of September 2021

 Boivin pearl and amethyst ‘Nail Head’ brooch, circa 1930, featured in the Bonhams London Jewels auction of September 2021

Boivin pearl and amethyst ‘Nail Head’ brooch, circa 1930, featured in the Bonhams London Jewels auction of September 2021

 Loris Abate diamond and gem-set sailing yacht brooch, featured in the Bonhams London Jewels auction of September 2021

Loris Abate diamond and gem-set sailing yacht brooch, featured in the Bonhams London Jewels auction of September 2021

Although I have only mentioned a handful of pieces here, the London Jewels sale at Bonhams is a treat for 21st century jewellery aficionados (and contains some swoon-worthy Grima pieces that will delight collectors). Part of what I love about browsing auction catalogues ahead of significant sales is reading the stories, noting the reports and finding out the provenance. With this information, one is not simply buying a piece of jewellery, but a snapshot of history and a moment in time.

Brilliant and Black: Sotheby’s Dedicates Exhibition to Black Jewellery Designers

continue reading

Essential Passion: The Artistic Pursuits of Mehragin Rahmati of Mergin Jewelry 

Jewellery can be thoughtful and insular, or it can be effusive and bold and full of character that makes it stand out from the crowd. I would put the colourful and charismatic creations of Mehragin Rahmati into the latter camp because of their attention-grabbing silhouettes, unusual structures, and confident mineral palettes.

by Katerina Perez

Maestro of Masterpieces: New High Jewels in the Picchiotti Classics Collection

Ahead of this year’s Couture show in Las Vegas, Picchiotti has revealed some of the latest additions to its high jewellery repertoire, including new suites in the Picchiotti Classics collection.

by Sarah Jordan

Reasons to Shop: The Moments that Demand a Fresh Jewellery Purchase 

There's no rule that says you need a reason to buy a new piece of jewellery, but sometimes, a little encouragement makes the decision even more exciting. If you're looking for a playful excuse to book your next jewellery appointment, here are a few irresistible reasons to treat yourself.

by Hirshi Sujanti

Grecian Glamour: The Designers Preparing to Spotlight Greek Style at JCK Las Vegas

Recently, I was approached by the organisers of a special ‘Greek mission’ who are supporting 11 independent designers and brands as they seek to make their mark at JCK Las Vegas from June 6-9, 2025. Below, I would like to introduce you to each of the businesses participating in this incredible showcase of Greek design, ingenuity and craftsmanship.

by Katerina Perez

Naked Attraction: The Best High Jewellery of the 2025 Cannes Film Festival 

Here’s a rundown of some of the best Cannes jewellery looks from the 78th annual festival (May 13-24), including the likes of Dakota Johnson, Angelina Jolie, and Natalie Portman, who all make striking jewellery the star of their ensembles

by Sarah Jordan

In Conversation: Discussing Paraiba — The Legacy of a Color with Vogue Singapore

The conversation encouraged both myself and Kevin Ferreira, my co-author, to recall exactly why we wrote Paraiba: The Legacy of a Color, and I am pleased to share more with you below

by Katerina Perez

Semi-Precious vs Precious Gemstones: Why the Old Labels No Longer Work

I can’t count the number of times I’ve asked myself: what really sets so-called precious and semi-precious stonesapart? Is it their rarity? Colour? Durability? Value? Or is it simply tradition—an outdated hierarchy we’ve inherited without question

by Katerina Perez

Larger than Life: New Mineral Masterpieces and Global Adventures with Margot McKinney 

Let’s take a closer look at the pieces and places that have helped to shape the Margot McKinney brand over the last 12 months, including the rather sensational Marina, Aurora and Bloem necklaces

by Katerina Perez

Male Adornment: The Evolution of Men’s Jewellery from the 1400s Until Today

Men's jewellery is often overlooked, yet its history is both rich and cyclical. Over the past six centuries, the popularity of male adornments has fluctuated, reflecting shifts in fashion, status, and cultural values. Here, Amanda Triossi examines the reasons behind male jewellery, along with its periods of abundance and decline.

by Amanda Triossi

Perfect Proposal: The Top 10 Engagement Ring Mistakes to Avoid 

The moment you start thinking about proposing, everything shifts. Ordinary things become significant: dinner out, a walk in the park, a glance at their jewellery box. And then comes "the ring": a symbol of love, yes, but also a silent spokesperson for everything you feel and hope for. No pressure, right?

by Claire Roberts

Couture Show 2025: The Top 10 Debutants Heading to Las Vegas 

The much anticipated Couture Show will return to Wynn Las Vegas from June 4-8, 2025, shining a spotlight on established design talent, new creatives, and international brands that are vying for attention on the global stage. Just like in previous years, I am focusing my attention on the debutants

by Katerina Perez

Designing the Future: Revealing the Winners of the Katerina Perez x Osmium Institute Design Contest

What a ride it has been, witnessing such pure creative energy and original thinking, especially with a material as rare and futuristic as osmium

by Katerina Perez

Latest Stories

Add articles and images to your favourites. Just

Legacy of Love:The Dreamlike Jewels of Emirati Designer Mariyeh Ghelichkhani

During our meeting in Dubai, we spoke about the importance of family, the sweetness of finding joy through creativity, and the ability to translate dreamy visions and deep feelings into wearable pieces…

by Katerina Perez

Jewels Katerina Perez Loves

Continue Reading

Writing Adventures:Co-Authoring the Book

Paraiba: The Legacy of a Color

by Katerina Perez

Jewellery Insights straight to your inbox

Style Guide

By using this website, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. View our Privacy Policy for more information.