"a fire opal the size of a pigeon's egg"

Fire Opal
Creative Commons Attribution Share AlikeFire Opal - Credit: Didier Descouens
 Opal is a relation of quartz; its ability to diffract light means it can appear as any colour in the visible spectrum.  Although most opals are sourced in Australia, the fire opal – or Girasol – is usually found in the state of Querétaro in Mexico.  Their colour is generally orange, leaning more towards yellow or red depending on the conditions in which the stone formed.  This led to them becoming a symbol of passionate love throughout many cultures since ancient times.  The Mayans and the Aztecs named it ‘Quetzalitzlipyollitli’, meaning ‘the stone of the bird of paradise’.  Despite its fire, it is not one of the harder stones, and it requires firm settings if it is made into jewellery

Overall – a very heady choice for a wedding ring.