The Correct Statement:
The correct statement is option 'A', i.e., "Feldspars are not aluminosilicates."

Explanation:
Feldspars are actually aluminosilicates, which means they are composed of both aluminum and silicon. They are one of the most abundant minerals in the Earth's crust and are commonly found in igneous, metamorphic, and sedimentary rocks.

What are Feldspars?
Feldspars are a group of rock-forming minerals that make up a significant portion of the Earth's crust. They are classified as tectosilicates, which means they have a three-dimensional framework structure composed of interconnected SiO4 tetrahedra.

Composition of Feldspars:
Feldspars are complex minerals composed of a combination of aluminum, silicon, and oxygen, along with other elements such as potassium, sodium, calcium, or barium. The general chemical formula of feldspars can be expressed as (K, Na, Ca)(Al, Si)4O8.

Types of Feldspars:
There are two main types of feldspars: potassium feldspars (K-feldspars) and plagioclase feldspars. K-feldspars contain potassium as their dominant cation, while plagioclase feldspars contain a combination of sodium and calcium as their dominant cations.

Uses of Feldspars:
Feldspars have various industrial uses due to their unique properties. Some common uses include:
1. Ceramics: Feldspars are used in the production of ceramics, including tiles, pottery, and porcelain.
2. Glassmaking: Feldspars are a key ingredient in the glass industry, as they help to reduce the melting temperature and improve the transparency of glass.
3. Paints and Coatings: Feldspars are used as fillers in paints, coatings, and pigments, improving their durability, opacity, and weather resistance.
4. Abrasives: Certain types of feldspars, such as orthoclase, are used as abrasives in products like toothpaste and scouring powders.
5. Gemstones: Some varieties of feldspars, such as moonstone and sunstone, are valued as gemstones for their unique optical properties.

Conclusion:
In conclusion, option 'A' is the incorrect statement. Feldspars are indeed aluminosilicates, which are composed of both aluminum and silicon. They are important minerals with various industrial uses and are abundant in the Earth's crust.