Veela Hair would make for a changeable core, which some may call temperamental, especially if they have little cause to work with the core, or with Veela. Like Veela themselves their hair makes for a potentially volatile core, able to change it’s tune at a moments notice. As a result wands cored with Veela hair are usually found in the hands of those with some (usually recent) Veela ancestry, with the hair donated by a full-Veela relative, in order to be made into a wand. Hairs not donated, but taken, have a tendency of angering the Veela in question, thus, despite the poor view frequently taken of Veela, all legally made wands with Veela cores must have had the hair donated freely.
Power-wise Veela hair is a relatively powerful core, midway between the strength of the oft-used Unicorn hair, and the much prized Phoenix feather, due to the human size of Veela, and their powerful personal magic. Wands cored with Veela hair may tend toward Transfiguration, much as Veela themselves do, with their shape-altering abilities, but this does depend on the wood and the wands owner.