I've gotten my hopes up one too many times over a storewide beauty sale. Luxury brands are notorious for not going on sale, and it never fails that there's an asterisk followed by miniscule fine-print stating that the discounts exclude anything worth getting excited about.

Which is why the one-day best customer event at Bluemercury is a diamond in the rough. Once a year, the high-end beauty chain gives shoppers 10 percent off purchases over $100, 15 percent off purchase over $175, and 20 percent off purchase over $250. All 90-plus luxury and niche beauty brands Bluemercury carries—La Mer, Bobbi Brown, Trish McEvoy, Laura Mercier, NARS, Fresh, Oribe, SkinCeuticals, Diptyque—are included.

The sale is usually announced only to Bluemercury's top customers, but anyone can attend. Hit the one-day event today at the Lincoln Park Bluemercury (3512 N. Southport Ave., 773-868-1300) from 2 to 8 p.m. or head to the Highland Park Bluemercury (638 Central Ave., 847-432-7200) on Tuesday, December 10 from 2 to 9 p.m.