Described as Venetian, specialist Clive Hillier had been told that the consignor's father-in-law, who had inherited them many years before, believed they had been made in this most exotic of materials to light the way of a sedan chair.
An alternative view is that they may have been lamps for a gondola, but detailed research was not conclusive.
They stood just shy of 6ft (1.83m) high and were in original condition, save a missing wrythen glass shade.
"I kept the estimate down to £5000-8000 (large unworked narwhal tusks can bring this much on their own). But they were so original, in very good condition and just the thing for the decorative market that I expected them to make more," he toldATG.
At the sale on September 9, four phone bidders competed with two in the room up to around £12,000, after which the latter two continued up to £18,000 when the hammer fell to the London trade.
The buyer's premium was 17.5%.