Odd 1887 Shilling

My guess is that it has been in a timber drawer, but without anything lying on top of it. The species of timber would have to be important, such as red cedar which can over a long time produce acidic vapour from the resin which found naturally in this species of timber.

Red cedar, (not western red cedar), was commonly used for cabinet making at the time this coin was struck, but is rare as hen's teeth now, and is extremely valuable.

When I am referring to timber species here, the red cedar is Australian only, (toona australis). There are quite a number of species of timber around the world that are known as 'cedar'.

Very impressive. That's something I would love to see in person.