by Robin Hansen, Curator, Minerals and Gemstones, NHM Earth Sciences
As part of the Galley Enhancements Programme to refresh the Museum’s Earth Galleries Ground Floor, we’ve been working on the specimens to improve the experience for visitors, improve collection visibility and update the science.
At the Natural History Museum our work is based on scientific collecting to support research on the natural world. In our collections we hold naturally occurring chemical elements in many different forms, compounds and combinations, so with many others, we are marking the 150 years since the periodic table was published in 1869 by the Russian chemist Dmitri Mendeleev by celebrating the International Year of the Periodic Table. We are aiming to cover all of the elements in our collections in a blog, starting with osmium, rhodium and iridium.
Most geological collections we hear about in the news are the prettiest, oldest, youngest, largest, smallest, rarest, most expensive or have some exciting story related to them that ties them to the evolution of our planet. Dinosaurs, human remains and meteorites are particularly popular. Over the last year we’ve embarked on a major curatorial project rehousing something that is the opposite – an unglamorous collection of bags of crushed rock.
With lengthening days, intermittent showers and the creeping return of greenery to the streets, there is one thing about this time of year that we can all rejoice in: the return of spring and summer. There is no denying that warmer weather, brighter days and leafy walks to work is enough to lift anyone’s spirits, and here at the Museum we have been putting together a collection of gifts in honor of one of the most significant happenings of the season. With the distant chiming of bells in mind we have put together a collection of gifts and small favours true to the natural beauty of a very momentous occasion – and no, it’s not our recent 135th birthday either.
Summer is of course the season of weddings, and what better way to celebrate this beautiful event than by some small reminders of the natural splendor of the earth, incorporated into the big day. But where did wedding favours come from? And why do we still use them? Surprisingly, this centuries old tradition has quite an extensive history of it’s own!
Some meteorites, called CI chondrites, contain quite a lot of water; more than 15% of their total weight. Scientists have suggested that impacts by meteorites like these could have delivered water to the early Earth. The water in CI chondrites is locked up in minerals produced by aqueous alteration processes on the meteorite’s parent asteroid, billions of years ago. It has been very hard to study these minerals due to their small size, but new work carried out by the Meteorite Group at the Natural History Museum has been able to quantify the abundance of these minerals.
The minerals produced by aqueous alteration (including phyllosilicates, carbonates, sulphides and oxides) are typically less than one micron in size (the width of a human hair is around 100 microns!). They are very important, despite their small size, because they are major carriers of water in meteorites. We need to know how much of a meteorite is made of these minerals in order to fully understand fundamental things such as the physical and chemical conditions of aqueous alteration, and what the original starting mineralogy of asteroids was like.