Earthly and ethereal: Minerals, rocks and gems

No prize jewel or decoration, this silver ore was part of the King’s mineralogical collection.

George III ruled Great Britain and Ireland between 1760 and 1820 when many of the founding collections of the Natural History Museum were made.

His passion for science and art had an enormous influence on British cultural life.

This piece was donated to the British Museum, an offshoot of which would become to Natural History Museum, alongside many important artistic and scientific objects from his royal library.

Even before King George III helped popularise the new enlightenment culture, one man was amassing a truly illuminating collection.

Sir Hans Sloane (1660-1753) collected mineral, botanical, and zoological specimens, ethnographic objects, antiquities, prints, drawings, books and manuscripts – although to the public he is perhaps most famous as bringing a milk chocolate recipe from Jamaica.

Upon his death his collections were acquired for the nation by an Act of Parliament that created the British Museum, and later the Natural History Museum.

This sapphire turban button was a treasure in Sloane’s collection, which described as ‘a large sapphire of the finest deep colour set in a crystal button, inlaid with gold’.

Not all collections contain striking objects, but can be equally as historically important.

This sample of granite, a rock formed by the cooling and crystallisation of magma, was collected by geologists on Robert Falcon Scott’s fated Terra Nova expedition (1910–13) to Antarctica.

Although the expedition is famous for Scott and a small team reaching the pole, all of whom subsequently perished on the return journey, it also had a wide range of scientific aims, including discovering more about the formation, composition and age of the continent.

The Natural History Museum contains collections from many important historical expeditions, including Charles Darwin’s voyage on the Beagle and the Challenger expedition, a pioneering oceanographic voyage.

These specimens are still studied as more modern techniques become available, and Museum scientists continue to collect on expeditions across the world, from fossils in Morocco to plants in Peru.

Some collections of mineralogical specimens are important not because their collectors were famous, but because of their scientific integrity.

Frederick Noel Ashcroft took up mineral collecting while a student at Oxford before the First World War.

He became interested in the minerals of Switzerland, but he realised that although most of the major minerals were known and represented in collections, their precise location was rarely recorded.

The collection he amassed from southern Switzerland was relatively small compared to the likes of Sir Hans Sloane, but was complete and meticulously documented, with the location of each sample photographed.

He also took care to collect only the highest quality specimens, resulting in a collection even the Swiss came to England to visit after he gifted it to the Natural History Museum.

Not all gems are simply to be marvelled at.

The Koh-I-Noor diamond was unveiled at the 1851 Great Exhibition in Hyde Park, when it was the largest diamond in the world.

Despite the fanfare, some thought it just didn’t sparkle as it ought to.

It was re-cut the following year, resulting in two-fifths less weight but a great deal more sparkle.

The Natural History Museum has in its collection a plaster cast of the original cut as well as display models of the two shapes.

To find out why the original didn’t live up to the hype, Museum researchers programmed the shapes into a computer model.

They found the original cut limited internal reflections of light, making the appearance of the diamond duller.

They even simulated the lighting of the Great Exhibition and were able to confirm reports that the diamond was at its most brilliant between 14.00-15.00, when the Sun was at an advantageous angle.

Some gems are important not for their beauty but for their rarity.

Painite, named for its discoverer British mineralogist Arthur Pain, was until recently one of the world’s rarest minerals – it was in the Guinness book of world records as the world’s rarest gem.

It was first found in Myanmar in the 1950s, and right up until 2005 there were only around 25 specimens worldwide, several of which are held at the Museum.

Although still extremely rare, new deposits have now been discovered in Mogok region of Myanmar.

The Museum collection not only contains rare minerals but fictional ones too – well, almost.

New minerals are still being discovered, and this one – found in Serbia in 2006 and identified by Museum scientists – has properties out of this world.

The composition is nearly identical to that given for the fictional mineral kryptonite, Superman’s only weakness.

Jadarite’s chemical formula sodium lithium boron silicate hydroxide is almost the same as that given for kryptonite in the film Superman Returns.

Some items in our collection actually are out of this world.

The Wold Cottage meteorite was the first in the UK to actually be seen crashing to Earth, in December 1795.

Ploughman John Shipley looked up from his work on the Wold Cottage estate in Yorkshire to see this stone fall a few metres from where he stood.

A year earlier, German physicist Ernst Chladni began to record similar events, and suggested the stones fell from space.

However, he was ridiculed for his theory, the preferred idea being that they were blasted into the air by volcanoes.

But with no active volcanoes in Yorkshire, how could the Wold Cottage landing be explained?

The event prompted the first serious investigation into the origins of meteorites.

In the end, Chladni was proved right; the stones were very similar to each other but were like nothing found on Earth.

They must have had the same origin: space.

All meteorites are rare, but some are rarer than others.

The Tissint meteorite is exceptional as it is believed to be a chunk of Mars, and an incredibly well-preserved piece at that.

The Museum has several Martian meteorites, identified by their unique composition, but this one is described by our meteorite curator as 'the most important meteorite to have fallen in 100 years’.

Witnessed falling to Earth in Morocco in 2011, fragments of the Tissint meteorite are thought to have been knocked off the surface of Mars 700,000 years ago.

The meteorite fragment at the Museum is intensively studied by our scientists, not least because it contains unique evidence of water weathering on the Mars' ancient surface.

Meteorite impacts not only give us insights into the makings of the Solar System, but can also produce minerals useful for our civilisation.

The Sudbury impact crater in Canada was created by a large meteorite impact 1.8 billion years ago.

The crater is one of the world’s most important sources of nickel and copper, which formed from a pool of molten rock that filled the crater after the impact.

This copper-bearing sample is being researched by Museum scientists, who are investigating how copper and nickel separated during the molten phase of the rocks.

Many of the samples in the Museum’s collections are related to the UK’s rich mining heritage.

This is a sample from the Geevor tin mine in Cornwall, which was in operation from 1911-1990.

One of the Museum’s curators took this specimen to a show-and-tell at Parliament to promote the UK’s ‘geodiversity’ and museums’ role in protecting and promoting it.

Many of us are familiar with the concept of biodiversity – the variety of plants, animals and other living things that underpin whole ecosystems.

Geodiversity is the variety of rocks, minerals, fossils, landforms and soils, together with the natural processes that shape them, as a foundation for life and our society.

With this definition in mind, the Geevor tin mine sample is an ideal key specimen – having been formed 290 million years ago and influenced our industrial age and the local culture of Cornwall.