A miniature mineral specimen is one that measures more than 3.8 cm but does not exceed 6 cm in any dimension. This definition is based on the idea that a 2-inch (5.1 cm) cube can be placed over the specimen, with all bottom edges of the cube resting on the same flat surface as the specimen.
Many collectors deliberately focus only on miniature specimens because they are easy to handle, store, and display, and they are economical for those with limited space.
Miniature minerals are often abbreviated as MIN or MINI's.
Image: Example of a Miniature mineral specimen: Amethyst from the Chala Mine (Bulgaria) measuring 5.8 × 2.3 × 2.6 cm.