From Guild Wars 2 Wiki
Brandstone Chunk nodes can be revealed by players at Brandstone Impact Sites through use of the Brandstone Multitool, in Domain of Istan. Ore can be extracted with Extraction Beam or an Orichalcum Mining Pick (using a pick produces less ore). Five nodes appear with each fallen meteor.
- Brandstone Multitool - for how to find Brandstone Chunks.