Geodes can be lined with an amazing variety of minerals, the
most common being quartz and calcite. Less common would be azurite,
malachite, apophyllite, chalcopyrite, rhodocrosite, cavansite, and
stilbite among others. Geodes contain an amazing variety of
minerals, the most common of which are rock crystal, amethyst,
chalcedony, calcite, and not so commonly, rhodocrosite, azurite,
malachite, apophyllite, stilbite, chalcopyrite, among others.