What feature distinguishes demantoid from other garnets?

Demantoid garnet is distinguished from other garnets primarily by its strong dispersion. Dispersion refers to the ability of a gemstone to separate white light into its component colors, creating a fiery appearance. Demantoid garnet exhibits high levels of dispersion, often compared to that of diamond, which gives it a unique, vibrant sparkle that sets it apart from other members of the garnet family.

While inclusions of horsetail are a notable characteristic of demantoid and can be used to identify this gemstone, weakly visible inclusions do not define the entire gem's identity as strongly as its optical properties do. Clarity can also vary widely among colored stones, making it less of a distinguishing factor in this context. Size is not typically a characteristic that defines the demantoid, as it can be found in various sizes, similar to other garnets. Thus, it is the exceptional dispersion of light that serves as the hallmark feature of demantoid garnet.