The geologist’s tool kit

Dr Neale Monks

Of course, you can enjoy a fun and productive geological field trip using nothing more than your eyes to spot interesting specimens and your hands to collect them. At localities like Sheppey, where fossils are constantly being weathered out of soft clay, you can find shark teeth, shells, plant remains and all sorts of other fossils in the shingle. Wrap up your findings in newspaper or paper towel and off you go.

However, having at least a basic tool kit will make your excursions into the field safer and more productive. In this article, I will look at the essential parts of a geologist’s tool kit and review some of the options available to you.

Safety gear

Geological fieldwork is educational, entertaining and great exercise, but it has to be done properly to be done safely. Part of that is wearing the right gear.

A hard hat is an essential part of any field worker’s kit. To start with, it increases the wearer’s visibility, making it easier to keep a group together in poor light. A hard hat also provides some protection against falling debris. Obviously, no hard hat can stop boulders, which is why you should never work beneath an unstable cliff. However, a hard hat will give useful protection from small bits of stone that fall from relatively stable cliffs, from time to time.

Safety goggles protect your eyes from the chips that fly about when rocks are hit with hammers. Modern safety goggles give secure, all-round protection without being heavy or uncomfortable to wear. They will also fit over spectacles.

Gloves keep your hands warm and provide protection from abrasive or sharp rocks. Rigger gloves are a particular favourite among field geologists, having grips on the palm and fingers that make it easier to hold onto tools, such as hammers, even in cold and wet weather.

Hammers

A good hammer is at the heart of any geologist’s tool kit. There is a wide range of hammers on the market, and choosing between them can be confusing. The main differences come down to durability, weight and the shape of the head.

The most durable hammers are drop forged steel hammers, of which the American Estwing brand is probably the best known. These hammers are formed from a single piece of steel giving them unparalleled strength and durability. On the other hand, drop forged hammers are significantly more expensive than any other type of hammer. Nonetheless, this type of hammer has long been popular among experienced professional and amateur geologists alike, as a reliable tool that lasts a lifetime.

Two-piece hammers are a bit less durable because of the joint between the head and the shaft. On the other hand, these hammers are much less expensive and, in the case of wooden and fibreglass hammers, much lighter as well. This makes them particularly attractive to someone looking for a good first hammer to use as they start exploring the geological world around them.

Hammers with wooden handles are usually the least expensive models on the market. While a variety of woods are used, the best are made from hickory – a strong, slightly flexible wood that makes for a light, comfortable hammer. As well as being easier to use and carry around, the wood absorbs some of the shock of impact, reducing hand strain. In particular, children find wooden hammers ideal instruments. The chief drawback of wooden-handled hammers is that the joint between the head and the shaft gradually weakens with use and, after a few years of heavy use, it is very likely that the hammer will need to be replaced.

While sharing the lightness and shock absorbing characteristics of wood, fibreglass is much more durable. So, while hammers with fibreglass handles are a bit more expensive than wooden ones, many users find them a good compromise between cost, comfort, weight and durability.

The top end of the two-piece hammer market is filled with hammers that have tubular steel handles. On the plus side, these hammers are very durable and a good one, properly looked after, will last for many years. However, steel hammers are noticeably less comfortable to use than wooden and fibre glass-handled hammers because the steel conducts vibrations from the point of impact to the user’s hand. A thick rubber handle around the steel shaft helps somewhat, as will gloves. However, but many users still find these hammers (as well as drop forged hammers mentioned earlier) quite hard work.

Hammers are supplied with heads of different weights, ranging from 225g (8oz) hammers at the one end, to heavy-duty hammers weighing 900g (24oz) or more at the other. The heavier the hammer, the more force it produces at the point of impact, but this isn’t necessarily a good thing. Too much force will shatter some types of geological specimens, particularly fossils. However, if your interests centre around igneous rather than sedimentary rocks, then a heavy hammer will probably be essential – simply because a lightweight hammer won’t break open those sorts of rocks at all. A popular, all-round choice is the 450g (16oz) hammer, though children will find the 225 g (8oz) hammer a bit easier to use.

Hammer heads typically have a flat end intended to be used in conjunction with a rock chisel. At the opposite end from the flat end is either a chisel or pick.

Chisel ends are preferred for general work, being good for splitting sediments and pulling away vegetation and also weathered rock covering the site of interest. Pick ends are more useful for cracking and shattering rocks by imparting the maximum possible force on the smallest possible point. Therefore, palaeontologists tend to prefer chisel ends so that they can work open sedimentary rocks while looking for fossils, while hard rock geologists favour pick ends for exposing minerals.

Chisels

Rock chisels are chiefly used to split sedimentary rocks. Many geologists like to have a set of chisels of different sizes, each suited to particularly tasks. The larger chisels will be used in the field to break open rocks along their bedding planes, exposing things like fossils and sedimentary structures. Smaller chisels are used for more delicate work, often at home for cleaning up fossils, by chipping away carefully at excess rock around the specimens.

The quality of rock chisels is largely reflected in their price. Cold steel chisels are relatively inexpensive, but tend to lose their sharpness more quickly than chrome-vanadium steel alloy chisels. All chisels last longer if used properly and this means, in part, using the right sort of chisel for the particular task at hand. Using a small, sharp chisel for cracking open a dense sort of rock will blunt even the best-made tools.

A neat feature on many modern chisels is a rubber safety guard that prevents your hammer from hitting your hand should you miss the top of the chisel. Especially, in cold and wet conditions, this sort of mishap can be all too common!

Picks

A geological pick is essentially a hammer that doesn’t have a flat end, but instead has a chisel at one end and a pick at the other. Picks are definitely specialist tools, but they can be extremely useful. Picks are wonderful for working away at relatively friable rocks like chalk and clay. Mattocks are larger versions of picks and useful for heavy duty excavating, where large amounts of weathered rock need to be removed before the pristine geology underneath can be investigated.

Trowels

Not all sediments are rock-solid and, for working at clays and sands, trowels can be much more useful. Where a hammer would simply get gummed up and make a mess, a trowel can be used to slice and sift soft sediments carefully. For geologists in Southern England especially, where these types of sediments are common, trowels are essential bits of kit.

Etchers and air pens

Once you get back home, you’ll need to clean up your specimens, and that’s where etchers come in. An etcher is essentially a mounted needle that is used to scratch away at the excess rock obscuring a specimen. Softer rocks, such as clay, chalk, and sandstone, can usually be worked away very effectively using etchers. A good etcher will have a tungsten-carbide tip that will stay sharp for a long time.

Serious collectors, who want to clean their fossils more quickly, will often turn to an air pen instead of an etcher. Air pens use compressed air to vibrate the tungsten-carbide tip incredibly quickly and this lets the user remove sediment from specimens in a fraction of the time it takes using an etcher. However, air pens are expensive and, if used carelessly, their very effectiveness can end up removing detail from a specimen just as easily as they remove excess sediment.

Sieves and forceps

Geologists working with sand and clay often find sieves to be essential components of their tool kit. By sifting sediment in bulk, they can quickly find things like shark teeth, mammal bones and other small fossils that would be easily overlooked if hunted for one at a time. Geological sieves are graded by the size of particles they trap so, by pushing sediment through a succession of ever-finer sieves, smaller and small fossils can be extracted.

Once you’ve cleaned the sand or clay in this way, you can use forceps (tweezers) to handle small fossils without damaging them. Bones and small shells are especially fragile.

Hand lenses and magnifying boxes

Few geologists go into the field without a hand lens. These typically have the lens protected by a cover that slides away and a lanyard that makes the lens easy to wear around the neck. As well as their obvious usefulness for examining small specimens, hand lenses can also be used to reveal subtle detail on larger specimens. The basic hand lens will have a single magnification (often x5 to x10), while higher-end models may have multiple lenses for a range of magnification.

Magnifying boxes are popular with geologists who collect relatively small specimens such as sharks’ teeth. As well as making the specimen easier to see, the box also gives the specimen a certain amount of protection, making it possible to display the specimen to groups of people without fear of it getting damaged.

Specimen bags and waterproof marker pens

Plastic specimen bags have become a ubiquitous part of field geology, because they are so very useful. Specimens or samples of rock can be placed in the bags and then the bag is labeled using a waterproof marker pen. By putting information such as the locality, horizon and bed onto the bag, the all-important provenance of the specimen is secured. Plastic bags don’t tear as easily as newspaper does, so provide much better protection while the specimen is in transit.

Off you go …

For someone wanting to make a start in geology, either for fun or for part of an undergraduate degree, a starter pack of tools is often the best-value way to begin. These packs will come with a variety of useful tools, including the all-important hammer, safety goggles, chisels and hand lenses. Once you’ve figured out which bits of the science you enjoy the most, you can then add additional tools as required. If fossil hunting is your thing, then etchers and fine chisels may be the tools you need, while hard rock geologists looking for crystals and ores will definitely find a pick more useful.

Maps and books are always useful but, depending on where you live, you’ll probably want to find publications that are most relevant to the geological opportunities in your area. If you live in Aberdeen, having a monograph on the Lower Lias of Somerset is not very helpful! However, some geology suppliers produce starter packs tailor-made for specific regions of the country, such as the UKGE Fossil Hunting Starter Kit PRO.

Without a doubt though, one of the best ways to get started is to go on an organised field trip with one of the many geological clubs and societies in the United Kingdom.

Happy rock hunting!

Neale Monks (born 1971) is a former palaeontologist at the Natural History Museum in London, where he worked primarily on heteromorph ammonites about which he has also written extensively for Deposits. He now writes about tropical fish and Macintosh computers.