The crystal and the surrounding crater are clearly
visible on the world map east of Serenity Temple.
The dominating landmark "Pockmark crystal" is an exceedingly large Searing crystal. It resides in the center of a large crater, the lowest portion being full of tar, within northern Pockmark Flats. The tar it lies within is surrounded by three Earth Altars, used for summoning a Stone Golem.
In Guild Wars 2, the area surrounding the crystal is called "Pockmark Roughs"; the giant crystal itself is worshipped as the "Tail of the Star God" by local grawls.
|The Guild Wars 2 Wiki has an article on Tail of the Star God.|