The only way is Essex crystal

This Victorian stickpin c.1875 shows the crystal cabochon dome and hand painted reverse intaglio of a terrier or Italian greyhound, which would have been painted with a single hair brush; the crystal intaglio is a mere 1.5cm diam. It was offered for sale by Graisons Fine Jewellery (online jewellery store) for $1400. Image: Graisons Fine Jewellery.

Popular in Victorian times were these rock crystal domes engraved on the reverse side and painstakingly detailed in oils.