Quartz on Limonite Boxwork

Minerals: Quartz, Limonite.
– Field of View: 7 cm (appr.)
– Found: Mexico (San Luis Potosi)
Photo: Leo Jahaan

This is a particularly interesting type of mineralogical occurrence, as there were 3 different minerals involved in forming the final result. First there was a sulfide mineral which over time completely dissolved, leaving hollow honeycomb-like cavities known as ‘boxwork’. Within this hollow boxwork structure, thin interconnecting sheets of Limonite formed on surfaces. At a later date transparent Quartz formed a druse coating.