Amortentia is the most powerful love potion in the world. It is distinctive for its mother-of-pearl sheen, and steam rises from the potion in spirals. Amortentia smells different to each person, according to what attracts them.
Amortentia doesn't really create love, but causes a powerful infatuation or obsession. It is an incredibly dangerous and powerful potion, more so arguably than Veritaserum, Polyjuice Potion or Felix Felicis, as the power of obsessive love is great.
Professor Slughorn prepares a cauldron of Amortentia to show his sixth-year Potions students.