What is a significant factor in determining the value of jet?

The significant factor in determining the value of jet is its origin and color saturation. Jet, a type of lignite that has been used for ornamental purposes, derives its value from where it is sourced and the richness of its black color. High-quality jet is usually a deep, intense black, which is highly sought after for jewelry and carvings.

The origin can also influence value, as jet from certain locations, like Whitby in England, is historically more prized due to its distinctive attributes and historical significance. This combination of origin and color saturation is paramount for appraisers and collectors, as these elements impact the overall aesthetic and desirability of the piece. Other factors like availability, size, carat weight, cut quality, and transparency can play roles in valuation but are not as critical as the influence of origin and color saturation in the context of jet.