Martian minerals, true-colour Spirit rover image. The minerals (white) were uncovered during one of the rover's turning manoeuvres. The rover (part of which is seen at bottom left), then used its robotic arm and tools to investigate the deposits. The trench is 30 centimetres wide. The minerals appear to be iron-rich sulphates and other chemical salts. This may indicate that water was once present here. The colours of the image were created by combining camera filters to approximate what a human would see. The enhanced false-colour image is R360/245. This image was obtained with the panoramic camera on 12 January 2006, on the 721st Martian day of the rover's mission.