The locality a mineral is found in is a crucial aspect in mineral identification. Minerals occur in environments, or regions suitable for a particular mineral's formation. As a result, certain locations can only yield specific minerals. This factor can rule out possible minerals that do not occur in an environment a specimen was found in.

Many minerals also form distinct specimens in certain localities. The stalactitic, banded Rhodochrosite from Catamarca, Argentina is unique to its location; such rhodochrosite specimens are not found anywhere else in the world. Therefore, if one purchases a banded rhodochrosite specimen without a locality name, it is known that the specimen is from Catamarca, Argentina. The reverse is also true. If one knows that the locality of a pink, banded specimen in his collection is from Catamarca, Argentina, he can assume it is rhodochrosite. However, this can cause confusion in certain cases. For example, Franklinite, a black octahedral mineral, is only found in Franklin and Ogdensburg, New Jersey. People automatically assume any black octahedral mineral from Franklin is Franklinite. However, Spinel, Gahnite, and Magnetite also occur in Franklin and Ogdensburg, and can be very similar in appearance.

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