Hot-stone massages are a common service at most spas across the country.

Gemstone massages…well, forgive the pun, but they’re pretty rare.

The Spa at Trump is one of the few venues in the world where guests can (almost) literally shower themselves in diamonds. The service was introduced at its Las Vegas and Chicago locations in 2008 (a year so tense for the U.S. consumer that any sort of massage would have been welcome), and it’s still available in only four of the Trump Hotel Collection’s nine hotels to date.

The massage technique is nothing particularly special – it’s a simple hands-on, full-body massage that last 90 minutes – but the oils used are some of the most exclusive in the world. Rachel Knapp, spa director at The Trump Soho in New York, says that unlike most massage oils, which are comprised of only 10% or 20% essential oils (i.e. – lavender, bergamot, etc.) and the rest carrier oil (i.e. – sesame oil, olive oil, etc.), these particular oils contain 100% essential oils and no carrier oil at all, making them quite special and expensive.

And then there’s that whole being-infused-with-gemstones thing. The oil comes in four different varieties – diamond, emerald, sapphire and ruby – each of which contains crushed pieces of the actual stone.

“You can actually see the gemstones in the oil,” Knapp says.

Knapp explains that each oil was designed to fulfill a certain customer “intention” – for instance, the emerald is meant to satisfy those who want to feel purified, the diamond is for balance, the ruby is for revitalization and the sapphire is for calm. Knapp says the stones contain certain energetic and therapeutic properties that, in combination with the essential oils, give customers the feeling they seek. “Balance” and “calm” are the most popular selections, she says.

At $295 midweek or $325 on weekends, the gemstone treatments are among the luxury spa’s most expensive offerings. The spa also offers some other eye-poppingly pricey services, including a 60-minute deep-tissue massage for $190and a 60-minute facial for $235.

Knapp says that spa guests are accustomed to spending big money, but still find the gemstone treatments particularly intriguing.

“They think it’s a little over the top, but they like it,” she says.