First-grade agarwood can cost as much as $100,000 per kilogram. Why is it so expensive?

For thousands of years, agarwood has been known as "The Wood of the Gods." First-grade agarwood can cost as much as $100,000 per kilogram, making it one of the most expensive raw materials in the world. Aquilaria malaccensis is a tree native to the rainforests of southeast Asia. The healthy heartwood inside Aquilaria trees is pale, odorless, and worthless. In order for this tree to produce any agarwood, it must first become infected with mold. So how does this infection process work? What is agarwood used for? And what makes it so valuable?