Feldspathoid: meaning, definitions and examples
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feldspathoid
[ ˈfɛldspəˌtɔɪd ]
geology mineral
A feldspathoid is a mineral that is chemically similar to feldspar but lacks or has a lower silica content. These minerals typically contain alkali metals and aluminum, and are found in igneous rocks, especially those with a low silica content. Feldspathoids are important for understanding the formation and evolution of certain types of volcanic rocks.
Synonyms
leucite, nepheline, sodalite.
Examples of usage
- The rock sample contained several feldspathoid minerals.
- Researchers studied feldspathoid composition to understand volcanic activity.
- Feldspathoids are crucial in classifying certain igneous rocks.
Etymology
The term 'feldspathoid' is derived from the German word 'Feldspat' meaning 'feldspar' combined with the suffix '-oid' which denotes similarity or resemblance. The origins of feldspar trace back to the late 18th century, derived from the Swedish language, where 'fält' means 'field' and 'spat' is derived from 'spat' which means 'to split'. The term 'feldspathoid' was first introduced in the mid-19th century as mineralogists began to categorize minerals based on their chemical compositions and crystal structures. This categorization was essential for crystal chemistry and petrology, helping geologists and mineralogists better understand the complex processes that form different rock types in the Earth's crust. The distinction between feldspar and feldspathoid is significant, particularly in igneous petrology, where these minerals indicate specific conditions under which rocks have formed.