The Colour by Rose Tremain

Joseph and Harriet Blackstone emigrate from Norfolk to New Zealand in search of new beginnings and prosperity. But the harsh land near Christchurch where they settle threatens to destroy them almost before they begin. When Joseph finds gold in the creek he is seized by a rapturous obsession with the voluptuous riches awaiting him deep in the earth. Abandoning his farm and family, he sets off alone for the new gold-fields over the Southern Alps, a moral wilderness where many others, under the seductive dreams of 'the colour', are violently rushing to their destinies. By turns both moving and terrifying, it is a story of the quest for the impossible, an attempt to mine the complexities of love and in the process discover the sacrifices to be made in the pursuit of happiness.