Marilyn Monroe had little interest in jewellery but she did adore the simple pearl necklace given to her by Joe DiMaggio on their honeymoon in January 1954. So much so that she wore it again at their divorce hearing later that year.

Elizabeth Taylor, on the other hand, acquired blingy, expensive jewellery like nobody's business – "Big girls need big diamonds," she once said. Her collection included the spectacular 16th-century La Peregrina pearl which was part of the Spanish crown jewels.

Monroe and Taylor are represented in a show devoted to pearls, opening at the V&A on Saturday.

Neither probably knew the grimmer truth of what they were wearing. "The pearls are formed around the larvae from a tapeworm coming from the excrement of other animals," said the show's co-curator, Hubert Bari. "The people marketing them prefer to say 'it is so fantastic: your necklace was made from a grain of sand'. It is better to speak about a grain of sand than to speak about a piece of shit from a stingray."

The grain of sand myth is so entrenched that the V&A has included a video showing precisely how pearls are formed – how tiny tapeworm larvae that live in the digestive systems of animals such as sharks and stingrays are excreted and then, very rarely, manage to get into water-filtering shellfish. Some get trapped between the shell and the outer epithelial tissue, and it is from this that the pearl emerges and the larvae dissolves.

The formation of pearls is so rare that fishermen would find a natural pearl in perhaps one in 2,000 shells – or even one in 50,000 for some of the stunners in the V&A show. The jewellery historian Beatriz Chadour-Sampson, the show's other co-curator, said most other gems, whether emeralds, diamonds or opals, were subject to the vagaries of fashion. "The amazing phenomenon of pearls is that they're global, both east and west wore pearls over centuries. And there's been a continuous passion for pearls over centuries, it never ceases really and that is very different to other gemstones."

The most coveted and expensive pearls are judged on their roundness, perfection and lustre, and come in shades dictated by their shells, from white to pistachio green, pink, gold and aubergine. More than 200 pieces of jewellery are going on display at the V&A show which is an expanded version of an exhibition staged in Doha, Qatar. Visitors might be dazzled by the beauty, staggered at the effort that goes into getting even a single pearl, or fascinated by the stories behind the pieces.

One such piece is the pearl-drop earring that Charles I wore as he went to the executioner's block in 1649, coming with a convincing note of authentication from Queen Mary II, who wrote: "This pearle was taken out of ye King my grandfather's ear after he was beheaded & given ye Princess Royall" – referring to Charles's eldest daughter Mary, later Mary of Orange. The show includes examples of pearl jewellery use going back as far as Roman times in the first century AD, with people who could afford it mostly ignoring the distaste expressed by Pliny the Elder. He complained about the "new rich" in his Naturalis Historia, written just before he died in the eruption of Vesuvius. "Women spend more money on their ears in pearl earrings, than on any other part of their person."

The exhibition also shows how pearls have often been seen as a sign of power and authority, in the medieval period, or as a symbol of purity and chastity, and that pearls can symbolise both love and sorrow.

From more recent times there are the Bulgari pearl earrings that Taylor wore in the 1973 film Ash Wednesday, alongside Monroe's pearl necklace given by the baseball superstar DiMaggio, made by the company of the pioneer of cultured pearls, Kokichi Mikimoto. He was the man who in the early 20th century developed the methods needed to produce cultured pearls on an industrial scale. "He wanted every woman to be adorned by a pearl necklace," said Chadour-Sampson. "He honoured the pearl very much."

The exhibition is being staged in partnership with the Qatar Museums Authority, and exhibits are being shown in genuine safes from 1850-1910, highlighting the out-of-reach nature of pearls for most mortals.

But the exhibition will acknowledge that things are changing. One display features buckets of far more affordable Chinese pearls, grown on a vast, industrial scale in rice fields and on housing estates. "Is it devaluation of the pearl or is it Mikimoto's dream come true?" said Chadour-Sampson. "It is a matter of interpretation."