Approx. 2 inches. Plume Agate gets its name from the patterns of mineral growths within the silicates. The shapes of these minerals look more like feathers, flowers, or flames rather than trees like Moss or Dendritic Agate. Agate enhances mental function, improving concentration, perception and analytical abilities. It soothes and calms, healing inner anger or tension and creates a sense of security and safety.