Is Bytownite a Feldspar?

Bytownite is a calcium rich member of the plagioclase solid solution series of feldspar minerals with composition between anorthite and labradorite.

Is feldspar a labradorite?

Labradorite ((Ca, Na)(Al, Si)₄O₈) is a feldspar mineral first identified in Labrador, Canada, which can display an iridescent effect. Labradorite is an intermediate to calcic member of the plagioclase series.

What is an example of feldspar?

Orthoclase, labradorite and oligoclase are examples of feldspar minerals that have been faceted.