Tears of the Wyrm

At will, Great Wyrms can 'cry', resulting in 'tears' from one or all six of its eyes. Doing this process damaged the eyes somewhat, so we don't want it happening too often or risking damage.
The main benefit of these tears, as you might expect given the magical inclination of dragons and their eyes in particular, is a massive boost to magical ability. That is a massive, permanent, boost. Even just a single tear can make an untrained civilian on the level with a magus in raw magical might. It doesn't impart the same amount of control, unfortunately, and as such can be rather dangerous to the uninitiated. It's better and more worthwhile for the tears to be ingested by someone who is at least trained in the movement and processing of large amounts of Aether.
The internal well of Aether increases exponentially, while the Aether 'flows' (that is to say the internal channels through which Aether travels) share an equal increase in width and toughness, increasing their general effectiveness. Considering these are active changes to the body, it remains possible that the ingestion of too many Tears of the Wyrm at once could cause damage, but it's  a rare enough material that has never been a problem to be tested before.
The tears can have their magical energy siphoned off in the same way that a Eyes might, but in a far more limited fashion. The power is potent, but it's comparatively minuscule when stood next to a fully intact and functioning dragon eye.

Type

Biomaterial

Value

Whole kingdoms. Medium ones.

Rarity

Incredibly

Odor

Vanilla-like

Taste

Sweet, like amarreto but not the same.

Color

gold-amber

During the age of the Wyrms, namely the First Lunar and Astral Eras, their tears were a common reward. Common enough, in fact, that several modern hypotheses and theories believe that humanities current average magical level is due to the rewards of dragon's tears that our early ancestors received while under the tutelage of dragons.
It's entirely possible that having another large amount of tears could lead to drastic changes within the human physiology, likely making us more generally powerful, but the Wyrms have far less inclined to give out their tears.