Cosmetics entrepreneur Susan Posnick won’t tell you her age. “Mary Kay used to say that a woman who would tell you her age would tell you anything,” she says with a grin. And it’s clear that Posnick holds dear every bit of advice she ever received from Mary Kay Ash, the late Dallas cosmetics mogul.

After working as Ash’s personal makeup artist for 18 years, from 1982 to 2000, Posnick says Ash told her that she, too, would someday have her own makeup line. But Posnick wasn’t convinced. To that, Ash replied, “Yes, you will… And when you do, you better put your name on it, because it makes you stand behind your product in a much different way.”

Turns out, Posnick says, Ash was right.

After being diagnosed with skin cancer in the late 1990s, Posnick discovered a niche for all-natural mineral makeup with built-in sun protection, after she found that none was available on the market. “I wanted to make beauty simple for women, and [to] make it easy to have sun protection,” she says.

In 2002, Susan Posnick Cosmetics was born. Today the company employs 14, including independent reps and contractors.

Posnick’s unique business journey began with a teaching degree in elementary education. “I had no idea what else to do,” says Posnick, who wound up teaching school in the Virgin Islands. It was there that she befriended a former advertising photographer from New York who introduced her to “the right people.”

Posnick soon turned a love she never thought could be lucrative—cosmetics—into a prosperous career as a makeup artist, painting the faces of everyone from Cindy Crawford and Tom Cruise to Roger Staubach and Troy Aikman.

She moved from New York to Dallas in the early ’80s at the behest of local modeling-industry mainstay Kim Dawson. Dallas “has been a great city to me,” says Posnick, who’s been here ever since. “I never felt like I hit a wall or a ceiling here. … This is a great city for women who want to be entrepreneurs.”

Today, Posnick’s cosmetics line is thriving. Though she declines to reveal sales figures, the line was picked up by Neiman Marcus in August. It’s also sold locally at Stanley Korshak and Forty Five Ten, as well as at numerous spas, apothecaries, doctor’s offices, hair salons, and other boutiques worldwide.

The line could be considered a clever blend of Bare Escentuals and Bobbi Brown, but Posnick likes to think she sets herself apart from the competition. “There’s nobody doing it the way that we’re doing it,” she says. For example, ColorFlo—the original and still the most popular product in the line—is foundation, powder, and sun protection all in one refillable cylinder, with a brush on the end.

Posnick’s next step in the entrepreneurial world is mastering the art of social media. The company recently launched a blog, as well as Facebook and Twitter accounts. Through social media, Posnick says, she’s trying to make the line more appealing to a younger generation.