What term describes the contrast between an inclusion and its host gem?

The term that describes the contrast between an inclusion and its host gem is relief. Relief refers to the visibility and prominent distinction of an inclusion against the background of the gemstone in which it is found. When an inclusion is in relief, it stands out due to differences in properties such as color, transparency, or refractive index. This contrast can enhance the visual appeal of the gemstone and provide important information regarding its origin and nature.

In contrast, texture relates to the surface characteristics of the gem itself or the overall feel of it rather than the interaction between an inclusion and the gem. Color is more about the hue of the gem rather than the specific relationship between its inclusions and host. Clarity refers to the overall presence of inclusions and blemishes in the gem, without specifically focusing on the contrast between any particular inclusion and the gemstone. Therefore, relief specifically addresses how inclusions are perceived in relation to the gem they inhabit, making it the correct term in this context.