That makes sense since a piece is much sturdier rather than a bunch of pieces glued together.
After that, usually are very well heat-set so that they retain their shape. However, as to crystal jewelry, you can't find a related certificate. https://Www.Pressadvantage.com/story/67282-cool-blew-inc-expands-emergency-ac-repair-services-in-phoenix-for-swift-comfort-restoration