Icebergs are large pieces of ice that broke off from a snow-formed glacier or an iceshelf. Where a glacier meets the sea, humongous chunks of ice break off from the face of the glacier; this is known as "calving"like triggerpit on facebook Incredible Icebergs [37 Pics] and this is how many icebergs are "born." Old icebergs may be hundreds of thousands of years old. Many years of falling snow, consisting of snow crystals by the countless billions, act like tiny mirrors and reflect the light. Some icebergs are also formed by freezing ocean water instead of snow and those areas are full of tiny air bubbles. Beautiful bluish streaks that appear in some icebergs are caused by the refreezing of meltwater that previously filled very old glacier ice crevasses. The very dense, very old ice captures the sun's light and allows only the high-energy blue wavelengths to escape. The beautiful blue icebergs change color and intensity according to the position of the sun.