12 Uses for Dragon's Blood -Major Clue or red herring?

[Susan Smith]

No: HPFGUIDX 71068

Just curious-does anyone know the 12 uses for Dragon's Blood?
Hermione was reviewing them for an exam in OOP; and Dumbledore is 
credited with their discovery in SS.

Too, does anyone know why JKR is fascinated by the number 12?  Is it 
because she is a fan of numerology as some have said?  Or is she 
trying to give us the greatest hint of all?  We see it as a "magical" 
number throughout all 5 books:
   
Neville is worth 12 of Malfoy; there are 12 large rooms in the 
Mysteries area; 12 OWLS is considered good (I think for Bill or 
Percy); Voldemort was in hiding for 12 years, Trelawney's second 
accurate prediction in POA says "has been chained these 12 years" 
etc. (I'm sure everyone can find a dozen (Ha Ha) more in each book.)  

Too, JKR introduces key characters or events and/or critical magical 
objects/spells in Chapter 12 of each book:

Book 1-Mirror of Erised
Book 2-Polyjuice Potion
Book 3-The Patronus   
Book 4-The Tri-wizard Tournament
Book 5-Dolores Umbridge

Further, if you buy the current theory that the souls of Slytherin 
and Gryffindor have passed through the centuries using the bodies of 
Good and Evil people as vessels we may need the valuable clue of the 
muber 12.  Speculation is that in 1945 the souls passed through 
Dumbledore and Grindewald, and Dd won.  Did Dd's victory have 
anything to do with dragon blood, and/or alchemy?  

Other vessels may have included: Tom Riddle, Voldemort, then 
Quirrell/Voldemort, now Voldemort again.  On the side of the Good, 
what if for some reason "it" left Dumbledore in the early 80s to 
reside with one of the Potters (because of the prophecy), and has 
passed along to Harry where it currently resides.  If this is the 
case, knowing how Dumbledore defeated Grindewald may be important.

Perhaps it involved dragon blood.  So, does anyone know the 12 uses 
of dragon blood?

A.G.