Where these two titles, "joven" and "gold" have been historically interchangeable, they actually refer to two different styles of Tequila that can be made in this category.
Jovens are any blanco Tequila that has an aged expression(reposado, añejo, or extra añejo) blended into it, and can result in lovely expressions. Combining blanco's youthful characteristics with the more mature qualities of an añejo or reposado, gold Tequila is truly the best of both worlds.
Gold Tequila is usually colored and flavored with oak extract, caramel, glycerin or other additives. Often they are mixto Tequilas that contain 51% agave sugars and 49% sugars from other sources.