Cover image:
Staurolite mica schist of the Middle to Late Ordovician Río Fuerte Formation, which outcrops in northern Sinaloa, Mexico.Staurolite porphyroblasts contain aligned inclusions of quartz and opaque minerals defining an internal foliation, which is oblique or orthogonal to the foliation outside the poikiloblasts. Also, an hourglass twin can be seen in one of the staurolite crystals. Further details can be found in the paper by Vega-Granillo et al. published in this issue.