Gemstones: Discover the rare and valuable with Robin Hansen

Diamonds, rubies, emeralds, and pearls – gemstones have been a source of delight, fascination and desire for many thousands of years, having historical, religious, spiritual and scientific significance.

Robin Hansen developed a love of minerals and geology while growing up in Perth, Western Australia. She now works as Curator, Minerals and Gemstones at the Natural History Museum, London, and has authored Gemstones: A Concise Reference Guide.

We asked Robin to share some precious insights into her love of gems!

You were raised in Perth – can you tell us where your love of gemstones and geology came from?

I can definitely blame my mother for my love of gems and minerals; she studied both Geology and Gemmology and is a huge inspiration to me.

Growing up in Perth we would go on family picnics into the hills, such as to Boulder Rock, and look at the different types of rocks and the textures they contained. I remember finding mica flakes in the concrete curb outside our house and spending ages trying to collect them.

When I went to university, I didn’t know what I wanted to be, only that I wanted to study science. Mum said, “Just try one unit of Geology, you might like it”. She was right, I was hooked, completing my degree at Curtin University with Honours in Geology. Gemstones were a natural extension to my fascination with rocks and minerals, and I later completed a Diploma in Gemmology.

You now have the role of Curator, Minerals and Gemstones at the Natural History Museum, London. Can you tell us about your role and the collection at the museum?

It had been my dream to work with the Mineral and Gem collection at the Natural History Museum since I visited London back in 2000. I walked into the Mineral Gallery in awe, spending hours looking at every specimen in the displays. I thought how do I get a job here, even if it is just to dust the minerals? An opening came up in 2015 and I was thrilled to get the role.

The collection consists of approximately 185,000 specimens, including around 4000 gemstones. It began in 1753 so it has an incredible history and I love to learn the stories behind different specimens. There are quite a few early specimens and gems that have come from Australia, including what we believe to be the first found specimen recognised as a diamond.

As a curator, I help to manage, document and care for the collection, ensuring it is preserved for future generations. We are fortunate to have so many minerals and gems on display in the museum, so a portion of my time is spent working on gallery displays. We also acquire new specimens, and facilitate access for visitors, research and tours. I can honestly say no day is ever the same.

What do you find so fascinating about gems?

I have always had a love of colour so the beautiful bright colours, and the sparkle, are an instant attraction to me, but as you delve deeper into the study of gems it is just fascinating. Why is it that colour, or what causes a gem to show a ‘cat’s eye’ or have a play of colour? Why do some gems appear brighter than others? How do the different gem minerals form? How do I identify a faceted red gemstone when it has no crystal shape or associated minerals, which could be one of many gems such as garnet, ruby, spinel, tourmaline or even glass?

The study of gems leads you to learn about the materials gems are made from – minerals, rocks, biogenic materials such as pearls, and human-made materials, and their physical and optical properties which both define them and determine how you identify them. The optical properties – that is the way light interacts with the gem material – will determine colour, sparkle and fire (those rainbow flashes diamonds are so famous for), and also influence how a gemstone will be fashioned.

The history behind gems is just as fascinating; they have been treasured for millennia, used for adornment, for magic, as symbols for power, and given as tokens of love, long before the written word and the first love letter!

It may be difficult to choose but are there particular gems you love or are interested in, and why?

It is incredibly difficult to choose! But I do have a few favourites. I really love tourmaline. It occurs in all the colours of the rainbow, including with multiple colour zones in one crystal, and makes a stunning gemstone. But it is also geologically fascinating – each different colour zone represents a change in the geological conditions as the crystal grew. Tourmaline is actually a group of minerals rather than a single mineral, currently containing around 40 different species, so the different colour zones may even be more than one tourmaline mineral in the same crystal.

My favourite is Paraíba Tourmaline; its neon blue-green colour has been described as ‘frozen Windex’ and is just spectacular. These tourmalines were first found in Paraíba state of Brazil in the 1980s, and were the first tourmalines recognised to contain copper which causes the colour. My dream is to obtain a large Paraíba gemstone for the collection.

I am also a big fan of the different garnet gemstones which come in a range of colours, not just the deep red most people are familiar with. And through my research for the book, I have a new-found respect for spinel. Red spinel was thought to be ruby for centuries – in fact many of the large red ‘rubies’ in Crown jewels are actually spinel. It is a durable gemstone with a range of vivid or pastel colours and bright sparkle, perfect for wearing in jewellery.

What do you hope people learn or discover in your book?

I have written the book to take the reader on a journey through the history of gems, how they each form and where they are found, their distinguishing features and properties which are used to identify them, their scientific value, and how they are fashioned and used.

I also discuss the many treatments that gemstones undergo to improve their appearance and durability, and human-made gemstones such as synthetic rubies. I discovered so many interesting facts during my research – such as that tourmalines were used to pull ashes from smoking pipes due to their electrical properties, and that the diamond on your finger is millions if not billions of years old, which is hard to wrap your head around.

I hope the book will be useful whether you are an amateur, a student or a professional gemmologist, or just want to have a better understanding of the gemstones in your jewellery. The study of gemmology has something for everyone as it crosscuts many disciplines including mineralogy, crystallography, chemistry, physics, geology, geography, history, religion and the arts.

Ultimately, I hope that it will give people a greater appreciation of gemstones, of their beauty and diversity, and that it will inspire them to learn more.

Author Robin Hansen developed a love of minerals and geology while growing up in her hometown of Perth, Western Australia.

She earned a Bachelor of Science from Curtin University, then worked for three years in the mining sector before moving to London and settling into a position in the private mineral collector business. During the following decade she complemented this role with a Diploma of Gemmology through the Gemmological Association of Great Britain and was awarded the prestigious Tully Medal. She now works as Curator, Minerals and Gemstones at the Natural History Museum, London.

Gemstones: A Concise Reference Guide reveals how each of the gem minerals forms, where they are found and mined, and how they are identified. The book also explains how to distinguish the real from the fake, as well as cutting and polishing techniques. The use of gemstones in adornment, from over 4,500 years ago to the present day, is also explored.

Gemstones: A Concise Reference Guide is available to purchase from our website and from all good bookstores.