Microcline

Microcline, sometimes referred to as amazonstone in the Realms, was a variety of feldspar.

Description
These ornamental stones were found in deep green to blue-green hues and cleaved easily so it took a skilled lapidarist to handle properly. Typically they are tumbled or cut cabochon. Polished microcline had a shimmer due to tiny cleavage cracks that reflected light. A typical stone had a base value of 10 gp.

Powers
Microcline could be used to make a substitute for squid and octopus ink that was the basis for many magical inks by grinding a microcline stone to powder and mixing it with the sap of a deciduous tree.