“Rose #2” (or Rose 2) is a standard industry color code used by manufacturers for lab-created synthetic corundum (synthetic sapphire/ruby).
Unlike synthetic hydrothermal quartz, these gems are produced using the Verneuil (Flame Fusion) method. This process melts high-purity aluminum oxide (Al₂O₃) to grow a single crystal boules with a highly consistent, light “rose pink” or “soft ruby pink” hue.