The Wheel of Time series, by Robert Jordan
(and later picked up by Brandon Sanderson after the original author's death in 2007)
The strands are weaved into different spells - one can infuse orange scent (hopefully), another would slice armor in half, etc. They come in five different flavours - the classical five elements of spirit, air, earth, fire and water. The source of these is known as the Power, which is divided into two halves - one called saidar, which is the female half, and saidin, which is the male half and tainted by the Dark Lord.
Until book 10.
It's a behemoth of a series, effectively quadruple the length of Lord of the Rings, and has much more diplomacy besides. I'd definitely recommend a few years to reading it.