Pentagonite 'Starburst'

Mineral(s): Pentagonite on Stilbite
Locality: Wagholi Quarries, Pune District, Maharashtra, India

What an explosion of color!

Here is a 2.2 cm aggregate of delicate blue pentagonite crystals lying on tiny snow white stilbite crystals which line a basalt matrix. The individual pentagonite crystals often form stick-like aggregates which can combine to form a burst-like formation. The lighter blue areas are where some minor damage has occurred.

Pentagonite is related to the more well-known cavansite - it has the same chemical formula, but a different crystal structure. Pentagonite is named after "the unusual twinning which produces an apparent five-fold symmetry" (according to Wikipedia).