She’s written hits for divas like Rihanna (“Diamonds”), Britney Spears (“Perfume”), and Celine Dion (“Loved Me Back to Life”). Now the 38-year-old Australian songstress seems destined to become a major star herself, despite her uneasiness about fame, on the strength of her sixth album. Sia’s knack for crafting hooky melodies is on full display here, with songs like the brooding dance number “Chandelier” and the stirring empowerment anthem “Eye of the Needle.” Her dark lyrics make these confessional compositions deeply personal. Sia, who has battled alcoholism and depression, bares her troubled soul on “Cellophane” and “Fire Meet Gasoline.” But she proves herself resilient on the innovative “Elastic Heart,” which first appeared on The Hunger Games: Catching Fire soundtrack. Stepping into the spotlight with a powerful collection of songs, Sia has clearly conquered at least some of her fears.