By Lynn Armstrong
Shippersea Bay, near Seaham, in the North East of England is home to a unique form of sea glass with colorful stripes, swirls of color, and organic-looking patterns. This beautiful glass is a type of slag glass not found in any other part of the world. Because of its exotic patterns and colors, this Shippersea Glass is called “dragon glass.”
No one knows where this unique slag glass came from, except that it was probably made with slag from the old glass or iron industries that stood along this rugged coastline over a hundred years ago. Slag glass is made by adding slag—the waste matter separated from metals during the smelting of ore—and mixing it with molten glass to create colorful streaks in the glass.
It’s conceivable that the pieces found at Shippersea were from early experiments to produce a local slag glass meant to rival the popular slag glass made in the mid-1800s by Sowerby Glassworks, Davidson Glassworks, and Greeners Glassworks in Gateshead, just north of Shippersea. In addition, the old bottleworks and ironworks in Shippersea dumped waste into the North Sea every day for over 70 years, so the slag glass could have been discarded from these factories.
While visiting Shippersea Bay, I became friends with a local fellow beachcomber, Paul Garbutt. He told me all he knew about these unusual forms of slag glass, and said he had taken samples to Durham University and the Hancock Museum in Newcastle (now the Great North Museum) to be tested. They confirmed that the “dragon egg” form of slag with the “barnacle” features are in fact 100% glass, but of poor quality, possibly the result of a mistake in glassmaking. So, the mystery continues!
Some of the locals have given the more appealing forms of slag glass nicknames, as “slag” just doesn’t describe these breathtaking pieces. Nicknames are "Dragon Eggs," "Dragon Glass," and "Boaty Blues," which gets its name from Shippersea, which is known as “Boaty Bay” by locals.
Collectively, all of this glass is known as Shippersea Glass, and can only be found at Shippersea Bay. The beach at Shippersea Bay isn’t as visible or accessible as Seaham, but for those adventurous enough to seek it out, the results are definitely worthwhile.
The safest way to Shippersea Bay is to cross over from Hawthorn Hive beach when the tide is out.
Learn more about extreme sea glass collecting at Shippersea Bay
This article appeared in the Beachcombing Magazine May/June 2019 issue.