On Wednesday, 26 April 1882, the Queenborough Chemical and Copperas Works have been auctioned off, heralding the demise of the copperas business on the Isle of Sheppey. Inexperienced copperas was used to make sulphuric acid or vitriol, chemical manures and dye stuffs.

“Being in Queenborough Citadel within the yr 1579 I discovered there one Mathias Falconer, A Brabander, who did in a furnace that he had erected there, trie to drawe very goode brimstone and copperas oute of a sure stone that’s gathered in nice loads upon the shoure close to untoe Minster on the isle”.

This extract is from ‘Lambard’s Perambulations of Kent’ and might be the earliest identified reference to a ‘chemical’ manufacturing facility in Britain.

fig 1 — Fig 1. Poster promoting the sale of Queenborough Chemical and Copperas Firm

The primary reference that I’ve that hyperlinks copperas with the gathering of fossils is discovered within the ‘Life and letters of Edward Lhwyd (second Keeper of the MUSEUM ASHMOLEANUM) Oxford March 28th. 1695’. Beneath is an excerpt from ‘A Museum of the Early seventeenth Century’ By Cyril Edward Nowill Bromhead, BA, FGS, FRGS. (Learn 18Th. June, 1947) referring to the Lhwyd letter:

“In case you may setle a correspondent within the Isle of Shepey to save lots of us all of the Crampstones the copras-women choose up for a month or two, I might now fall a couple of Lithologia Britannica: and so contrive it that the primary tome shall encompass onely enamel and bones of fish.”

(Sharks’ enamel have been referred to as ‘cramp stones’, as they have been floor up and used as a treatment for abdomen complaints.)

Copperas, as you’ll little question have gathered, is simply one other phrase for pyrite. The shape discovered on Sheppey is marcasite and is uninteresting inexperienced in color when recent, rapidly deteriorating to a rusty brown when uncovered on the seashore for a while. Chemically an identical (iron disulphide or FeS₂), pyrite and marcasite are very completely different in behaviour. The conventional gold colored pyrite has dense molecules and tends to be extra steady than the extra open molecules of the marcasite stones. Fossils preserved both as pyrite casts or containing pyrite inside bone are liable to pyrite decay. Many various strategies have been tried by collectors to protect pyrite specimens through the years, all with little or no long run success.

There’s nothing extra miserable to the fossil collector or the museum curator who, when inspecting prized or distinctive specimens, finds just a little heap of whitish mud, an eroded knowledge label and a discoloured field; even wood cupboards could be severely broken. It could be a couple of months, or a couple of years, of publicity to the air, however the inevitable decomposition will happen. The chief oxidisation merchandise are sulphuric acid and varied hydrated sulphates, primarily iron. The acid may also destroy related shell and bone materials. It’s now typically accepted that the decaying course of is brought on by a type of oxidisation and is triggered by publicity to humidity within the environment. Plainly the fossils take up moisture from the air, which reacts with the pyrite and the air. In exams below humid circumstances, the reactions could be catastrophic. Nonetheless, if water vapour is eliminated, the reactions are slowed down and may finally cease. The extra compact types of pyrite don’t take up moisture so readily and should solely proof decay by floor tarnishing.

Varied strategies have been tried through the years, each by museums and people, to cease the decay. Most have been unsuccessful. I don’t imagine that there’s a methodology that may assure full success, however I do assume that, with effort, the method could be slowed down. Within the following paragraphs, I shall try to explain among the strategies that I’ve tried with various levels of success.

fig 2 — Fig 2. An instance of an exploded fish cranium ( Scombrinus nuchalis ) because of pyrite illness from the Isle of Sheppey.

Earlier than remedy, you will need to wash all contaminants totally, reminiscent of clay and salts from the specimen. Salt is taken up by the specimen if it has been washed over by the tide. Wash the specimen with clear water. Some individuals wash their specimens with boiled or distilled water, however this can be a purely private selection. Change the water each day. The specimen ought to then be dried, however don’t dry the specimen artificially, as this could injury fragile specimens. Have a plentiful provide of self-seal plastic wallets or plastic jewelry packing containers of varied sizes. It is vitally essential that specimens are stored separate. One decaying specimen will infect others if involved. Retailer your specimens in a dry environment – damp outbuildings or sheds are completely unsuitable.

The chemical substances utilized by museums should not mentioned right here, as a result of I don’t know find out how to use them. If , it’s claimed that using ethanolamine thioglycollate has had some success treating decaying pyritised fossils. It’s also claimed to be efficient as a reagent for the removing of pyrite oxidisation merchandise. I’ve not had entry to this chemical, so can not remark.

After I first started amassing on Sheppey, I prevented pyrite fossils, solely amassing the bigger phosphatic and calcareous ones. I then found Folkestone and the fantastically preserved, however pyretic ammonites to be discovered there. Preservation grew to become an actual subject as among the older seashore collected specimens had been washed over by the ocean. As a result of the pyrite is porous, salts had been deposited at a molecular degree inside the specimen. That is why washing totally is so essential. If the nacreous shell of the specimen continues to be current, the issue is, find out how to (a) protect the shell and (b) deal with the pyrite.

Technique 1. The shell appears fabulous when moist, however at all times seems whitish and powdery when dry, typically falling away from the interior forged. The Folkestone ammonites must be washed very fastidiously with a delicate brush below softly operating water to take away any remaining clay. When dry, coat the shell, one facet at a time with ‘Sally Hanson’ ‘Exhausting as Nails’ varnish. That is strengthened with nylon which helps to stabilise the shell. Enable to dry after which place the specimen in a bowl of liquid paraffin. Virtually by magic over a day or two, the shell shall be remodeled from a creamy white to a wonderful iridescent pearly color brought on by the paraffin contained by the nylon. I’ve many glorious specimens as much as 15 years previous that present no indicators of degradation. This methodology works solely to reinforce the nacreous shell and isn’t helpful for preserving different fossils.

fig 3 — Fig three. Seaside part with areas of the brown marcasite type of pyrite.

Technique 2. This methodology is extra typically helpful and can be utilized for fossils from Sheppey or Folkestone and I might anticipate fossils from different places. That is my ‘Heath Robinson’ methodology, which I’ve been utilizing since 1995 with combined success. It has proved very helpful for many sorts of pyrite fossils, however not the little seeds and carbonaceous fossils from Sheppey. (I’ll clarify why just a little additional on.) My reasoning was quite simple – preserve the moisture away from the fossils and attempt to deal with them at a molecular degree. I searched round for a substance that might do that. I got here throughout ‘Ronseal moist rot wooden hardener’, a gooey resinous liquid, which was thinned with acetone. Very merely, after washing, the specimens have been immersed in a 20% resolution, which soaked by way of the fossil. If potential a vacuum surroundings will drive the liquid additional into the specimen. Nonetheless, I didn’t have one, so they simply stayed soaking for a couple of week. If the specimen got here out of the answer and appeared shiny, the answer was to sturdy so the entire course of was repeated with a weaker resolution. Hit or miss you may assume, however not one in all my little bivalves or gastropods from Sheppey have decayed in additional than ten years. If used on Folkestone ammonites, the shell is hardened, however the color stays a extra pure tone than the previous methodology.

The character of the woody seeds and twigs from Sheppey are very troublesome to protect. They’re a combination of carbonaceous materials and pyrite and, when drying, the woody materials shrinks whereas the pyrite stays the identical. Consequentially, the woody materials flakes off as quickly as drying begins. I’ve by no means efficiently maintained the soundness of those fossils utilizing these strategies. The nippa palm fruit is notoriously liable to decay. I’ve managed to delay decay as much as a few years by soaking the Nippa within the Ronseal liquid, whereas it’s nonetheless moist. The resins that it’s constituted of are likely to repel moisture and the acetone evaporates in a short time. When set, instantly immerse in a reasonably sturdy resolution of PVA, which dries to provide a versatile coating serving to to stabilise the carbonaceous materials. I feel that making a mould and casting in acrylic resin to make a reproduction is one of the simplest ways of protecting a reference to the seeds and woody fossils. The essential factor is to maintain your pyrite fossils dry, beneath 50% humidity. Tiny seeds could be stored in sealed containers with silica gel. So long as the silica is modified earlier than it will get too damp, the fossils could survive longer.

fig 4 — Fig four. Euhoplites truncates pyrite forged of a Cretaceous ammonite from Folkestone, Kent.

Technique three. This methodology is actually the identical in precept as methodology 2, besides that Paraloid is used instead of the Ronseal. Paraloid comes within the type of little plastic granules, that are soluble in acetone. It may be combined as a skinny resolution or as thick glue. It’s clear when dry. Fossils could be immersed in the identical approach as with the Ronseal and it’ll coat the fossils at a molecular degree if skinny sufficient. Nonetheless, it can take just a little trial and error to get the consistency proper. I’m informed that the NHM makes use of Paraloid of their conservation division. It’s helpful for a lot of conservation functions beside the remedy of pyrite.

(Each the above remedies are reversible by soaking in neat acetone. PVA will not be appropriate to be used within the remedy of pyrite. Industrial merchandise could include different chemical substances, which can be dangerous to the fossil.)

fig 5 — Fig 5. Nipa burtini seed fossil exhibiting indicators of superior decay.

What to do in case your specimen begins to indicate indicators of decay?

In case you catch it early sufficient, it could be potential to arrest the deterioration. The white powdery substance may be very acidic and can must be neutralised. Some fairly odd strategies have been really helpful previously, which concerned utilizing varied disinfectants apparently destroying the ‘micro organism’ and so stopping decay. I’ve by no means examined these strategies, so can not say how efficient they’re. The tactic that I exploit includes utilizing a powerful resolution of ammonia, a really harmful liquid, so it’s only really helpful if you’re skilled utilizing chemical substances of this sort. The thought will not be a brand new one and I’m positive that extra fashionable strategies are much less harmful and possibly more practical, however I don’t have entry to those. Merely put, the ammonia converts Ferrous Sulphides to Ferrous Oxides (rust), which is way much less dangerous to the specimen. It doesn’t assist if the specimen is simply too far gone, as it can most certainly find yourself as a small heap within the jar. The specimen have to be uncovered to an environment of 80% ammonia for a number of days. Don’t, below any circumstances, immerse the specimen within the ammonia resolution. The specimen should solely be uncovered to the fumes. The specimen will finally flip a heat rust color. This isn’t perfect, however is significantly better than dropping the specimen. Then deal with the specimen in one of many strategies outlined within the earlier paragraphs. Keep in mind to isolate your pyrite fossils in both sealable plastic wallets or in particular person plastic packing containers.

fig 6 — Fig 6. Brychetus meulleri efficiently handled for pyrite decay utilizing the Ammonia vapour approach.

It’s of the utmost significance that the ammonia chamber is sealed, in any other case the ammonia environment will dilute within the air and be ineffective. For very small specimens, I exploit a espresso jar with a glass lid with has a plastic seal, simply acquired from any grocery store and is good for the job. A small glass phial containing the ammonia is positioned with the specimen and left for a couple of days. For bigger specimens like fish skulls with pyrite inside the bone construction, I’ve used a bell jar sealed with petroleum jelly and, for very massive specimens, a sq. plastic storage bin positioned on glass and once more sealed with petroleum jelly. One a really massive fish cranium (Brychetus meulleri) – 30cm by 35cm – wanted to be uncovered to the ammonia for over two months, however has remained steady for the reason that remedy was accomplished 5 years in the past.

I’m not a conservator or a scientist, so the extra technical papers that I’ve learn to do with Pyrite conservation have solely been partially understood by me. Nonetheless, I’ve had some measure of success, fingers crossed, not dropping any of my specimens aside from among the extra woody and seed materials to the dreaded illness since I started amassing in 1995. In case you are suggested by the nicely that means to embed your specimen in clear casting resin, or to brush your specimens with sizzling clear candle wax or paraffin wax as has been instructed to me previously, don’t pay any consideration to them – they received’t work. The one positive methods to report for posterity your distinctive or essential specimen is to both make a forged of it or to it in order that, if the worst does occur (as it’s greater than possible will), proof of the specimen won’t be misplaced for future generations.

Additional studying

Some recommendations on preserving pyritised fossils, Jim Craig 1978.

Pyrite conservation half 1 historic features F. M. P. Howie, E-newsletter of the Geological curators group No9 April 1977.

Pyrite conservation half 2 F. M. P. Howie, E-newsletter of the Geological curators group No10 Sept. 1977.

Museum climatology and conservation of Palaeontological materials, F. M. P. Howie, Particular papers in palaeontology 22 1979.

Use of Ethanolamine Thioglycollate within the conservation of pyritised fossils, Lorraine Cornish and Adrian Doyle, Palaeontology Vol 27 pt 2 1984.

Conservation of your geological assortment, Seminar notes AMSSEE travelling geology curator, Simon Timberlake 1988.

An experimental Ammonia gasoline remedy methodology for oxidised pyretic mineral specimens, ICOM committee for conservation 1987 working group 15, Robert Waller.

Ronseal technical security knowledge sheet for Ronseal moist rot wooden hardener 2002.

A Museum of the Early seventeenth Century’ By Cyril Edward Nowill Bromhead, BA, FGS, FRGS. (Learn 18Th. June, 1947).

Early Science in Oxford by R. T. Gunther vol XIV.