I guess I don't have many investors among my readers but... who knows? It seems that this material is going to become a central component of new technologies and therefore it will probably see its value increasing.
Two days ago I posted on how this metal was central to plant photosynthesis as well to a newly discovered similar but artificial way of generating energy from the Sun, now I read that manganese is also key to a new type of electronic alloy that displays intermediate characteristics between magnet and semiconductor. This silicon, iron and manganese alloy appears to be very promising for soon-to-come new types of electronic circuits.
Manganese also has an array of other "traditional" applications. It's mined primarily in Australia, Burkina Faso, R.D. Congo, Brazil and Gabon.
Just an idea anyhow. Something alternative to the crisis bubble dynamics of "invest in gold".