These exceptions give the specimen a greater value. Anomalies Specimens of a mineral that exhibit unique, abnormal properties or are intrinsically different than normal specimens of the mineral fall under this category. Properties such as abnormal color, pseudomorphs, twinning, and odd crystals give a specimen extra value. A matrix shows the original uniqueness of the mineral. Crystals in a matrix should always be selected over freestanding crystals.
Some minerals are valuable for the useful elements they contain.
For example, many minerals composed of gold and silver may look ugly, but demand a high price because of their content. Rarity Obviously, rare minerals are more costly than more common ones. Extremely rare minerals have a great value, even if they look ugly. The opposite is also true. Some of the above properties can be artificially produced.