how do geologist use different type of crystal shapes to classify minerals

Geologists use different types of crystal shapes to classify minerals because crystals have a specific internal structure and atomic arrangement that give them their unique shapes. The following steps explain how geologists use crystal shapes to classify minerals:

1. Observation: Geologists begin by observing the external shape of a mineral or crystal. They note the symmetry, the number of faces, and their angles. This preliminary observation helps identify the crystal system to which the mineral belongs.

2. Crystal Systems: There are seven crystal systems: cubic, tetragonal, orthorhombic, monoclinic, triclinic, hexagonal, and trigonal. Each crystal system has specific characteristic shapes and angles.

3. Mineral Identification: Based on the crystal system, geologists can then narrow down the possible mineral identification of the sample. For example, if a crystal exhibits six equal faces at 90-degree angles, it likely belongs to the cubic crystal system, which is associated with minerals like pyrite or halite.

4. Additional Features: Crystal shape alone may not be enough to precisely identify a mineral. Geologists then consider other features like color, hardness, luster, cleavage, and specific gravity to confirm the mineral's identity.

5. Reference Materials: Geologists may reference mineral identification guides or consult databases to compare observed crystal shapes with known minerals.

By combining observations of crystal shapes with other physical properties, geologists can make informed classifications and identifications of minerals. It is important to note that while crystal shape is useful, it might not always be the sole determining factor, as some minerals can exhibit similar shapes. Therefore, it is crucial to consider multiple characteristics when classifying minerals.