Goldenpitch

Goldenpitch is a mineral named after its pitch-like black color with yellow parts. It's infamous among Equestrian miners for negative health effects linked to its prolonged exposure.

Health
Long term exposure to goldenpitch is known to cause tumors in the lungs and eventual death of lung disease in most creatures. Changelings, however, seem unaffected.

If encountered during mining, it is recommended to evacuate the mine, hermetically cover the goldenpitch and provide the miners with fresh air. If possible, Changelings should take care of these tasks, otherwise it is recommended to carry a respirator with an independent air supply.

Other effects
Goldenpitch causes the blackening of photographic plates.