Material Components and Foci

Arcana is a difficult art. One might have massive power, but that does not mean one is accurate. Components and Foci act as a mage's tools for directing the power they have amassed. Though non-mages may not understand it, they are just like an artist's brush, or the sight on a firearm.
Foci are the product of countless mage's pursuits. Now, as magic and technology grow in power and popularity, the process of creating, selling, and using foci has become commonplace. But there are still some things that a generic foci, no matter how powerful, can't reproduce.

Diamonds are an excellent example. Being used in resurrection because of their chemical composition, intrinsic value when cut, and how that cut represents wealth, effort, and time put into something. Spellcasters see how the effort, time and value creates a symbolic connection which calls the soul. Meanwhile scientists know that carbon makes an excellent binding element and part of a biological body. Now if only more people knew what a cut diamond really meant. Maybe we'd have more people who choose to stay in a relationship only when they truly love the other.
A strong component has power like that of diamonds behind it. The strength of symbolic connection to magic and the importance of it's composition to science. You might only need to understand one, but both aspects are necessary.

Access to generic foci has advanced the popularity of magic even despite the accessibility of science. Things like wands and staves carved with runes or symbols of the divine. However, a generic foci might be modified for more or different power if given the right resources. Others might spend excessive amounts of time to perfect their materials and methods to create such powerful items.