Hollandite in Amethyst Mineral Testing

Amethyst Roots have become increasingly popular over the past couple years at the major gem trade shows in the US.  Most of them have an unmistakable silhouette, large amethyst termination with phantoms tapering to a thin etched smoky base.  When we had the opportunity to purchase a batch with mysterious acicular black inclusions, we jumped on it!  The vendor referred to the inclusions as “toads” and left it at that.  My personal hunch was goethite sprays, and another mineralogist suggested Macfallite inclusions.

Here’s what the laboratory found:

  • The inclusions of radiating sprays are hollandite, a barium-bearing manganese oxide.
  • The inclusions are virtually iron-free.
  • This much less common than encountering sprays of goethite as inclusions.