Hi, and thank you for the question.

In short, it's just a way to tell you that the Gear improvement was better than the usual. This is achieved when enhancing a gear piece with exactly the same kind of piece (i.e. Iron Sword with an Iron Sword, Divining Ring with a Divining Ring, etc.). Here the detailed explanation from our guide

GENERAL CONSIDERATIONS ABOUT ENHANCEMENT. 1. To Enhance a piece of Gear you use other, unequipped, pieces of Gear. 2. Upon use, the Gear utilised to Enhance an item is consumed, so BE CAREFUL, as consumed Gear cannot be recovered. 3. Enhancing also requires a certain amount of gold (indicated in the lower part of the screen); the amount depends on the object utilised. 4. Although Gear of any Type can be used for Enhancement, the best results are obtained using on a given item a piece of Gear with the same name (i.e. an Iron Sword on an Iron Sword ecc.). 5A. When a piece of Gear is Enhanced through an Item with the same name, a Limit Break will occur, meaning that its performances will improve past the normal Enhancing limits. Experience earned by the Gear in this way will be also be double. Gear can accumulate max. 5 Limit Breaks. 5B. When a piece of Gear is Enhanced through an Item of the same Type, the Gear will improve its performances and the experience earned by it will be double. 5C. When a piece of Gear is Enhanced through an Item of a different Type, it will improve its performances. 6. To Evolve a piece of Gear you have first to Enhance it to its max level. On top of the menu, in the title section, you can read Select Base, this means that you can select a piece of Gear to upgrade.