Acalcium-rich nonfoliated rock that is often associated with economically valuable mineral deposits is
a. skarn
b. marble
c. phyllite
d. quartzite

which type of foliated metamorphic rock is an intermediate between slate and schist?
a. skarn
b. gneiss
c. phyllite
d. quartzite

The answer to the first question is B (marble).

Marble is a non- foliated  metamorphic rock that forms when limestone is subjected to the heat and pressure of metamorphism. it is  composed primarily of calcium carbonate and usually contains other minerals such as clay minerals, mica, quartz, iron oxide and graphite.

The answer to the second question is C (phyllite).

Phyllite has a texture that is intermediate between slate and schist. This results in slaty cleavage and shiny cleavage surfaces but grains that are still microscopic.