For CR123A: any made in USA or Japan cells (Panasonic, Surefire, Duracell, Rayovac, Energizer, etc).
For 18650: anything based on Panasonic NCR18650A cell (Xtar 3100mAh, Keeppower 3100mAh, Orbtronic 3100mAh, AW 3100mAh, RediLast 3100mAh, Intl-Outdoor 3100mAh, etc).
Avoid chinese CR123A's, because they sometimes explode when used in multi-cell flashlights (such as your Quark). Also avoid chinese 18650's, such as ultrafire, trustfire, GTL, etc - they don't perform well, wear out quickly, and sometimes even vent and/or explode.