Which two primary processes are used in the production of synthetic gems?

The primary processes used in the production of synthetic gems involve methods that allow for the controlled growth of crystals. The correct response that highlights this is the combination of "seed and pull." This method often refers to techniques such as the Czochralski process, where a small crystal seed is placed in molten material, and as the seed is slowly pulled upwards, a larger crystal forms around it. This method is essential for creating high-quality synthetic gemstones that have characteristics similar to their natural counterparts.

The other options do not accurately capture the techniques primarily used for synthetic gem production. "Melt and blow" relates more to glass production and does not apply to gem synthesis. "Melt and pulling" also implies aspects of material handling but lacks specificity in the context of crystal formation. "Cast and mold" typically refers to how certain materials, like resin or glass, are shaped but is not a standard method used in synthetic gem production.