On Tuesday, 17 March 2020, TRC volunteer Shelley Anderson wrote:
Like jet, bog oak involves fossilized trees. Trees such as oak, pine, yew or fir fell into rivers and were covered in silt and mud. In Ireland, such wood was trapped in peat bogs. The wood became stained a dark brown or black, as minerals seeped in, and became semi-fossilized.
This semi-fossilized wood is called bog oak, no matter what tree species is being used. Bog oak can range in age from a few centuries to over 5,000 years or older. The Victorians loved bog oak, not only in furniture, but also in jewellery. Its dark black colour made it popular for mourning jewellery.
By the 1850s new techniques had been developed that made working with bog oak less difficult and it was used in a wide variety of jewellery, from necklaces and bracelets to rings and brooches. It was sometimes passed off as, or mistaken for, jet, although bog oak is lighter and warmer to the touch, and the wood grain is sometimes noticeable.
You will frequently find for sale on the Internet late nineteenth century brooches made of bog oak, like the one pictured. Ireland was a good source of bog oak (as were the fens of England), and making jewellery from bog oak became a craft in nineteenth century Ireland.
Typically Irish motifs were often carved into the bog oak. These included the harp and the shamrock, which were often used to promote Irish crafts, similar to what was happening in the also popular Irish lace of the period. In general, such motifs were not used in jewellery made for mourning, but for that which was produced for other occasions.
Bog oak jewellery is still made today, although on a lesser scale, using wood sourced from Siberia, Ukraine or the Balkans.