Jewelry has zoomed ahead of cars in Knight Frank’s Luxury Investment Index, as appetite for modern pieces has accelerated.

   Jewelry prices rose 4% in the 12 months to June 30, the real-estate firm said in a recent research report, based mainly on data from Art Market Research. This compares with a 2% increase in the value of classic automotives, which have dominated the rankings in recent years.

  Over the past five years, jewelry prices have jumped 49%, and over the past decade they have leapt 142%, Knight Frank said. Pearls are still the top performer, gaining 285% over the past 10 years. However, their growth is starting to become more stable, in contrast to sharper increases in recent years, with more modern jewelry standing out instead.

  “There is a current trend for jewels from the post-war era, where the emphasis is on design, quality and workmanship,” said Jean Ghika, head of the London jewelry team at Bonhams auction house, which contributed to the Knight Frank report. “These pieces, often unique or in limited supply, are easy to wear, distinctive and increasingly sought after by discerning collectors.”

  Colored diamond prices have gained 89% in the past 10 years and 15% in the past half-decade, and were flat in the past year, according to data from the Fancy Color Research Foundation. The watch category advanced 65% over the decade, 24% over five years and 4% over 12 months.

   “Jewelry has always been a traditional store of portable wealth,” said Andrew Shirley, editor of Knight Frank’s Wealth Report. “There are few other investments of passion that you can simply scoop up, put in your pocket and run away with in an emergency.

  “Hopefully it won’t come to that for most of us, but it’s still reassuring to know that jewelry has been one of the best-performing asset classes in our Luxury Investment Index over the past 10 years,” he added.