note: purple in this list invariably means "indigo" in terms of the rainbow.
violet mana is associated with black magic.

Sources of Magic:

It is possible to find weak pieces of "solid" magic, or matra.
It is theoretically possible to create massive amounts of mana, or "light magic", with matra, even "pure" mana, but it is extremely difficult and impossible with current tech.

Refracted mana is available naturally in large quantities, the world is literally drenched in it.
It is easily concentrated into a visible form by those with magical ability, however doing so is likely to cause a side-effect.
For example, concentrating purple mana into a visible form often generates heat.
The actual effect produced depends on the way the mana was concentrated, what type of mana was concentrated, how skilled the person is, their level of affinity with that type of mana, etc.
Mana's visible form is similar to the appearance of light rays.

Magical artifacts can be found in limitted numbers in various ruins and old buildings, and sometimes in the form of heirlooms, etc.
Some of these were made using forms of magic or magical skills that have since been lost or are themselves very rare.
They are often cursed, and may cause the death of a user for not meeting certain criteria (a certain bloodline) or just because the user touched it.
The most powerful predate even the oldest ruins, and come from pre-elven civilizations that did not live in any lands that still exist.
They can take the most simple or ornate forms, including idols, jewelry, and weapons.

This category crosses slightly with the ones before and after it.
Magical stones and gems can be created using "gray" (purple) magic.
More powerful forms of this magic can create stones with varied effects, and it is even possible under certain circumstances for purple mana combined with other colors to create effects not otherwise available.
These stones and gems may be found as artifacts or heirlooms (gems in otherwise unmagical rings, for example), or they may be sold in stores, found at the scene of an attack, etc.
Obviously they can also be obtained from skilled magicians through other means than money (such as traveling with or Being such a magician).

The most powerful known physical source of magic is manamatra crystal.
No one alive can create it.
It requires massive amounts of mana and matra to create, or a dimensional rift, or both.
A large section of the core of The'elven is made up of this crystal.
If one could somehow get to this core, pieces of the crystal could be chipped off of the outside, however it would be quite difficult and beyond a certain very shallow depth (say one foot) the crystal is inpenetrable.
There are chips of the crystal that can be found on the surface of The'elven, but they are obviously incredibly rare.

Since all magic currently in The'elven originally came from a different dimension, a dimensional rift of some sort would be the most powerful source of magic.
There is such a rift near the core of the planet, caused by a large crack in the planetsized manamatra crystal trapped in the core (The'elven is quite a large planet).
A very powerful wizard could potentially use such a rift to create otherwise impossible magics, including powerful magical objects, as long as they had the ability to Create mana, matra, or manamatra.
Most wizards, even the most powerful, lack this ability because their experience is only in Using mana, and few if any have any experience using the Pure magic that can only exist in other dimensions.
An artifact created in another dimension without knowledge of these abilities would cease to be magical the moment it came back through the rift.