The $715 stackable ring showcases Meghan's "understated and timeless style," Zofia Day jewelry designer Lisette Polny tells PEOPLE

Okay, bagging Meghan Markle’s bespoke diamond engagement ring is definitely out of the question — but another of her favorite rings may actually be within reach.

Waving at the crowds last week during her second official royal engagement alongside fiancé Prince Harry, Meghan showed off a new gold-and-diamond ring from Zofia Day.

“It’s been a wonderful boost for my brand, and I am so grateful for Meghan’s support,” Lisette Polny, the designer of the up-and-coming brand, tells PEOPLE.

The Bar Stack Ring in 14-karat yellow gold retails for $715 and features pavé diamonds. It can be worn alone (as Meghan did) or stacked with other rings of the same style in different finishes.

“It’s such a simple design,” says Polny. “My company is still quite small, so for [Meghan] to select me was really quite an honor. I think it says something about her — I don’t think big brand names define her.”

Prince Harry and Meghan Markle Visit Reprezent
Credit: Max Mumby/Indigo/Getty; Zofia Day

It’s not the first time Meghan has shown her love for the brand, which was founded by Polny seven years ago and named after her daughter, Zofia. Last year, Meghan wore a pair of her Dash Ear Studs on the cover of Vanity Fair. “She was given them by a friend over two years ago, and I know she barely takes them off,” says the designer, adding, “I was obviously elated and honored.”

RELATED: Prince Harry Is Engaged to Meghan Markle! See the Ring!

With “four or five” pieces from Sofia Day in her collection, Meghan chose the bar ring with two other delicate (and unidentified) gold bands on her right hand to visit a radio station in Brixton on January 9.

“She seems to have a carefree, yet timeless style,” says Polny, who counts Jennifer Lawrence and Eva Longoria as clients. “I love that she is a natural beauty with an underlying sense of glamour — understated and timeless.”