This is a soda Feldspar and is triclinic, but exhibits the color characteristic of moonstone.
In the triclinic system there are three unequal axes and these intersections are all oblique.
They are triclinic, with cleavages meeting at approximately 86 degrees.
All the sodium, sodium-calcium, and calcium species are triclinic, except the rare monoclinic sodium felspar barbierite.
Relating to a crystal having three axes of different lengths intersecting at oblique angles. The mineral microcline (a type of feldspar) has triclinic crystals. See illustration at crystal.