One subset of these minerals has a value of 6 on the Mohs hardness scale, and on the Bowen's reaction series, these minerals make up the continuous branch.
One group of these minerals is further divided into a sanidine variety, and these minerals can be distinguished from a similar group of minerals because these minerals cleave across planes. These minerals have a K-type and are exemplified by labradorite. Members of this group of minerals have varying number of aluminum and silicon atoms, but all of these minerals have eight oxygen atoms. One subset of these minerals has a value of 6 on the Mohs hardness scale, and on the Bowen's reaction series, these minerals make up the continuous branch. For 10 points, name these minerals that make up a majority of the Earth's crust, which are classified as orthoclase or plagioclase
One group of these minerals is further divided into a sanidine variety, and these minerals can be distinguished from a similar group of minerals because these minerals cleave across planes.
feldspars [accept specific types]