What characteristic is NOT associated with an amorphous gemstone?

An amorphous gemstone is defined by its lack of a regular crystal structure. Unlike crystalline materials, which have a well-ordered arrangement of atoms or molecules, amorphous substances possess a disordered arrangement. This absence of a defined lattice structure is a key characteristic; thus, materials like opal or glass fall into this category. They exhibit properties such as isotropy, leading to a uniform appearance from various angles, contrasting with crystalline gemstones that demonstrate anisotropic behavior due to their ordered structure.

The lack of symmetrical arrangements and the absence of a defined lattice structure further differentiate amorphous materials from crystalline ones. While variable dispersion of light can happen in both amorphous and crystalline materials, it is not exclusive to either category, and thus doesn't serve as a defining characteristic of amorphous gemstones. Therefore, the identification of a regular crystal structure aligns with the characteristics of crystalline gemstones, not amorphous ones.