I think you are referring to a crystal.
crystal
crystal
Cristal's
The visible shape of a mineral's atomic pattern is called its crystal form. This refers to the geometric arrangement of atoms in a mineral, which can vary depending on the type of mineral and its crystal structure.
Mineral
A five sided geometric shape is called a pentagon.
equilateral triangle
A crystal shape refers to the geometric form or structure that a mineral naturally takes on when it solidifies. This can include shapes like cubes, hexagons, prisms, or even more complex forms depending on the mineral's atomic structure and growth conditions.
The total distance around a plane geometric shape, i.e. one drawn on a piece of paper, is called the shape's perimeter.
Simply a line is formed......
Arrangement of ions into a pattern in a mineral is referred to as crystal lattice structure. This structure gives minerals their characteristic geometric shape and physical properties.
A geometric shape that has 11 sides is called a "hendecagon" or "undecagon." Both terms are acceptable.