Hydrothermal mineralisation - 'the rock with with the hole'

The new ELI this week is "Interactive hydrothermal mineralisation; 'the rock with the hole' demo". The mineralising chemicals dissolved in hydrothermal fluids have two possible sources:
a) when rocks deep underground are heated, the fluids they contain are able to dissolve minerals in the surrounding rocks more readily, and then the hot fluids rise;
b) when igneous magmas cool, at a late stage of cooling, a watery fluid rich in mineralising chemicals often separates and rises.
Tin, lead, copper and iron are common metallic hydrothermal minerals.
This is one of many interactive, hands-on Earth-related activities which can all be found on our website.