The perception of this note is profoundly stark and often unsettling. It is most frequently described as a sharp, acrid bitter almond, distinct from the marzipan sweetness of culinary almond. Some also perceive a distinctly metallic, almost rusty or blood-like facet, which can be chillingly stark and clean, yet simultaneously heavy. It possesses an immediate, piercing intensity upon detection, often described as 'thin' or 'sheer' in its initial projection, yet it leaves an indelible, lingering impression. It does not evolve in the manner of a true perfumery note; rather, its character is singular, unwavering, and demands immediate attention. It is never a top, heart, or base note in any legitimate fragrance composition due to its inherent nature.