What do you call a city, region, or country with a large number of gemstone manufacturers?

A city, region, or country with a notable concentration of gemstone manufacturers is referred to as a cutting center. This term specifically denotes an area where gemstones, particularly diamonds and other valuable stones, are systematically cut and polished to enhance their beauty and value. Cutting centers are pivotal in the gemstone industry as they house skilled artisans and advanced machinery essential for transforming rough gemstones into finished products ready for the market.

In contrast, other terms like mining hub refer more to locations where gemstones are extracted from their natural settings, distribution zone encompasses areas focused on the logistics and movement of gemstones to different markets, and processing area tends to be broader, referring to the overall treatment of gemstones, which may not necessarily involve cutting and polishing specifically. Thus, cutting center is the most precise term for a region characterized by a high presence of gemstone manufacturers.