These are called striations.
Parallel lines seen on cleavage planes or crystal faces are usually caused by twinning, where two crystals grow together with a specific orientation relationship. This twinning can result in repeated patterns of parallel lines that are visible on the surface of the crystal.
Calcite has excellent cleavage in 3 directions, although they are not at 90 degrees. It can form prisms, rhombohedrons, or scalenohedrons that break into rhombohedrons.
Barium is an element which does not occur in pure (native) form on Earth. The two most common minerals in which barium occurs are Barite (BaSO4) and Witherite (BaCO3). According to its entry on wikipedia, Barite has Perfect cleavage parallel to base and prism faces: {001} Perfect, {210} Perfect, {010} Imperfect. I am unsure what sort of cleavage Witherite has.
A six-sided mineral crystal, also known as a hexagonal crystal, is characterized by its six symmetrical faces and typically forms in a hexagonal shape. Minerals such as quartz and beryl commonly exhibit this crystal system. The arrangement of atoms within the crystal lattice results in unique physical properties, including distinct cleavage patterns and specific optical characteristics. This structure is significant in mineralogy and crystallography, influencing how the mineral interacts with light and other materials.
The visibility of crystal faces on minerals depends on several factors, including the mineral's growth conditions and its environment. Some minerals may not have well-formed crystal faces due to rapid growth or space constraints, which can lead to irregular shapes. Additionally, factors like weathering, erosion, and mechanical damage can obscure or alter the crystal faces, making them less visible. Lastly, certain minerals may form in such a way that their crystal faces are inherently small or poorly developed.
Parallel lines seen on cleavage planes or crystal faces are usually caused by twinning, where two crystals grow together with a specific orientation relationship. This twinning can result in repeated patterns of parallel lines that are visible on the surface of the crystal.
cleavage surface are smooth and shiny as the fracture is due to weakness in the bonds between the atoms rather than a breakage. Crystal face is where the crystal development such as twinning take place.
Fluorite has four perfect cleavage planes that are parallel to the faces of an octahedron. This results in the mineral breaking into octahedral fragments when cleaved.
The property that causes galena to break into tiny cubes is its cleavage. Galena exhibits perfect cubic cleavage, meaning that when struck or broken, it tends to break along smooth, flat planes that are parallel to the cube faces of the crystal structure.
Halite crystals break into smaller crystals of the same shape due to the crystal structure and cleavage of the mineral. Halite has a cubic crystal structure and perfect cubic cleavage, which means it breaks along planes that are parallel to the faces of the cube, resulting in smaller crystals with the same cubic shape.
No. Consider two adjacent faces on a cuboid. Both planes are parallel to the edge at which the intersect. But the fact that they do intersect illustrates that they are not parallel.
No. The faces of a tetrahedron are equilateral triangles, but none of the faces is parallel to another one of the faces -- they could not be parallel, since by the definition of a tetrahedron, all the faces intersect(!) and parallel planes do not intersect.
A dodecahedron is a polyhedron with 12 faces, each of which is a regular pentagon. In a dodecahedron, the faces are not parallel to each other. The planes of the faces intersect at various angles, giving the dodecahedron its unique shape and properties.
Yes. The opposite ends of any right prism consists of two congruent and parallel faces. Two planes are parallel if the vertical distance between them is always the same.
In a polyhedron - a 3-dimensional object - a pair of parallel faces are two faces which lie in planes that are parallel to each other.Parallel faces need not be congruent. For example, consider a pyramid whose top is sliced off by a plane parallel to it base. The flat top and the base will be parallel faces but will not be congruent.
Minerals can have a cleavage plane, multiple cleavage planes, or no cleavage plane. A cleavage plane is an area of weakness in the crystalline structure where the mineral is prone to splitting.
Quartz vibrates when a voltage is applied between opposite faces of a crystal. The frequency of the vibration depends on the thickness of the crystal, and on the direction of the faces compared to the natural planes in the crystal structure.