The price isn’t want you’d expect.

If you’ve watched Bridgerton consistently over the years, you’ve likely noticed one key detail about almost every engagement ring to appear on the show: They’ve all featured pearls. Simon, the Duke of Hastings, proposed to Daphne Bridgerton in the series’ inaugural season with a petite piece with four pearls; in season two, Anthony Bridgerton popped the question with his mother Violet’s ring, which featured slightly more. This season, Colin Bridgerton followed suit, slipping a six-pearl piece onto his future bride’s ink-stained fingers (Lady Whistledown was in the middle of work when her suitor finally presented her with an engagement ring). And while some of these rings have featured tiny gemstones, their overpowering features have been those pretty treasures from the sea—but why? Why aren’t there any over-the-top, sparkling diamond engagement rings in Bridgerton, which is centered around a family with more money than most?

The answer ties back to the Georgian and Regency eras, which Bridgerton seemingly references. According to antique jewelry company Parkin & Gerrish, during these periods (which span from 1714-1837), diamonds were incredibly rare; they were reportedly only mined in Brazil and India and typically reserved for royalty. It makes sense, then, that you’d see plenty of diamonds on Queen Charlotte, but more colorful stones, like sapphires, rubies, emeralds, amethysts, and pink topaz, on the rest of the ton. As for how pearls fit in? They were a popular engagement ring choice during this time, says Oliviia Lee, a gemologist and design expert at Queensmith—and Bridgerton’s costume designers likely wanted Penelope and the rest of the show’s brides, for that matter, to remain truthful to the subject matter.

Penelope’s engagement ring honored the Georgian and Regency eras in more ways than one: even the piece’s clustered composition—called a flower-style halo, complete with six pearls arranged a central stone (which Lee actually believes is a white sapphire, not a diamond)—was a callback to the show’s historical context.

As for how much Penelope’s pearl engagement ring would cost if it were made today? The answer is lower than you might expect. “While the price point is less expensive, the cost of pearls depends on their quality, size, shape, color, surface, and quality. It also matters whether the pearls are natural or cultured, as natural pearls are rarer, so generally much more expensive,” she explains. “For the pearls in Penelope’s ring, the quality is quite hard to see. However, if they are cultured, then the estimated value of the ring would be around [$3,290] and if they are natural pearls, the value would increase to approximately [$4,050].” If you were interested in a real vintage pearl engagement ring from the Georgian or Regency periods, you could potentially pay more or less, depending on quality and the piece’s historical value; rings similar to Penelope’s seem to start around $1,000 online.