What is the primary characteristic of a negative crystal in a gemstone?

A negative crystal in a gemstone is characterized by being hollow and angular. This term refers to the specific structure where the crystal’s internal space is not filled with solid material, giving it a unique appearance compared to typical positive crystals, which are solid and structured. The angular nature of negative crystals can result in distinct geometric shapes, highlighting the difference in their formation.

While aspects such as enhancing brilliance or distinct colors might apply to certain gemstones, these features do not directly define what a negative crystal is. The idea of increasing weight is also irrelevant, as negative crystals are often less dense due to their hollow nature. Therefore, the essential defining trait of a negative crystal remains its hollow and angular structure.