"Boys keep back! They prefer the woman's touch, unicorns. Girls to the front, and approach with care, come on, easy does it. ..."
-- Professor Grubbly-Plank (OP15)
Magical pure-white horses with a single horn on their foreheads.
- Silver unicorn horns cost twenty-one Galleons each at the Apothecary in Diagon Alley (PS5)
- Mr. Ollivander uses unicorn tail hairs in some of his wands (see) (PS5)
- Unicorn blood is silver-blue in color and shines under moonlight (PS15)
- Unicorns are powerful magical creatures. It's not easy to catch them (PS15,)
- long slender legs, pearly-white mane
- horn and tail hair used as potion ingredients
- Unicorn hooves are golden.
- Unicorns prefer a woman's touch (FB,OP15).
- "They're a bit more trustin' when they're babies...don' mind boys so much...." -- Hagrid (GF10)
- Unicorn foals are pure gold. They turn silver when they're about two years old. They grow horns at around four. At about seven years old, they're fully grown and turn pure white.(GF10, FB)
- Voldemort's potion: unicorn blood and snake venom (GF33)
- Anyone who drinks unicorn's blood has a cursed life according to the centaur Firenze (PS15,Pm)
- Ronan states that when the unicorn is killed, that it is always the innocent that are the first to die.(PS15)
- Unicorn blood was used in the potion that resurrected Lord Voldemort.
- Unicorn horn is used in the Pottermore Antidote to Common Poisons.
- Unicorn tail hair is used in the Pottermore Beautification Potion.
Unicorns have always been an alluring concept to humans. Rowling captured the essence of this beautifully. Unicorns have been prevalent in fantasy since medieval times.
Unicorns in mythology are considered symbols of purity.
In the film version of "Harry Potter and the Half-Blood Prince" (2009), Ginny and Harry go to the Room of Requirement to get rid of the Half-Blood Prince Potions Book and a woven unicorn tapestry is hanging over the entrance (HBP/f) The famous tapestry is part of a series called "The Hunt for the Unicorn," and in this case titled "The Unicorn in Captivity and No Longer Dead" made before the 16th century in France, and now in The Cloisters museum in New York City (wikipedia). In the book the entrance to the Room of Requirement is actually near a tapestry of Barnabas the Barmy teaching ballet to trolls (OP18). Perhaps the filmmakers were using the unicorn as a symbol of Harry and Ginny's innocent love.