Facet

Facet BaseBase **·** 6★6★ Voice Artist:  Type: File:Attack icon.png[[:Category:|]] Base rarity: Facet BaseBase **·** 6★6★ Voice Artist:  Type: File:Attack icon.png[[:Category:|]] Base rarity:
Facet is a non-playable human, debuted in Story mode's Arc 1, Chapter 6.

# Profile

## Lore

Facet is a human scholar and researcher of light springs, a source of energy for all jewel princesses. Facet first appeared as the owner of a small lodge in the mountains visited by the protagonist team - Star Savior, Tinctura, Aqua Aura and Seraphinite. The team was seeking shelter from the blizzard created by the Zolne.

Facet is also the inventor of Illuminous Evolution Elixir in story as a results of her research, a required material for Illuminous alternate forms.

## Personality

Facet fully trusts her servant Trapezohedron, who self proclaims as a jewel princess to take care of her daily life and tasks, ranging from collecting light spring samples. Facet is unaware of how powerful her servant Trapezohedron really is in comparison to other jewel princesses, only assuming that all jewel princesses are as capable as Trapezohedron.

# Mineralogy

**Facets are flat faces on geometric shapes. The organization of naturally occurring facets was key to early developments in crystallography, since they reflect the underlying symmetry of the crystal structure. Gemstones commonly have facets cut into them in order to improve their appearance by allowing them to reflect light.**

The art of cutting a gem is an exacting procedure performed on a faceting machine. The ideal product of facet cutting is a gemstone that displays a pleasing balance of internal reflections of light known as brilliance, strong and colorful dispersion which is commonly referred to as "fire", and brightly colored flashes of reflected light known as scintillation. Typically transparent to translucent stones are faceted, although opaque materials may occasionally be faceted as the luster of the gem will produce appealing reflections. Pleonaste (black spinel) and black diamond are examples of opaque faceted gemstones.

The angles used for each facet play a crucial role in the final outcome of a gem. While the general facet arrangement of a particular gemstone cut may appear the same in any given gem material, the angles of each facet must be carefully adjusted to maximize the optical performance. The angles used will vary based on the refractive index of the gem material. When light passes through a gemstone and strikes a polished facet, the minimum angle possible for the facet to reflect the light back into the gemstone is called the critical angle. If the ray of light strikes a surface lower than this angle, it will leave the gem material instead of reflecting through the gem as brilliance. These lost light rays are sometimes referred to as "light leakage", and the effect caused by it is called "windowing" as the area will appear transparent and without brilliance. This is especially common in poorly cut commercial gemstones. Gemstones with higher refractive indexes generally make more desirable gemstones, the critical angle decreases as refractive indices increase, allowing for greater internal reflections as the light is less likely to escape.

Many crystals naturally grow in faceted shapes. For instance, common table salt forms cubes and quartz forms hexagonal prisms. These characteristic shapes are a consequence of the crystal structure of the material and the surface energy, as well as the general conditions under which the crystal formed.

The Bravais lattice of the crystal structure defines a set of possible "low-energy planes", which are usually planes on which the atoms are close-packed. For instance, a cubic crystal may have low-energy planes on the faces of the cube or on the diagonals. The planes are low-energy in the sense that if the crystal is cleaved along these planes, there will be relatively few broken bonds and a relatively small increase in energy over the unbroken crystal. Equivalently, these planes have a low surface energy. The planes with the lowest energy will form the largest facets, in order to minimize the overall thermodynamic free energy of the crystal. If the surface energy as a function of the planes is known, the equilibrium shape of the crystal may be found via the Wulff construction.

Growth conditions, including the surface the crystal is growing on top of (the substrate), may change the expected shape of the crystal; for instance, if the base of the crystal is under stress from the substrate, this may favor the crystal growing taller rather than growing outwards along the substrate. The surface energy, including the relative energies of the different planes, depend on many factors including the temperature, the composition of the surroundings (e.g. humidity), and the pressure.