Research was conducted into the possible use of zircon (ZrSiO{sub 4}) as a host phase for storage or disposal of excess weapons plutonium. Zircon is one of the most chemically durable minerals. Its structure can accommodate a variety of elements, including plutonium and uranium. Natural zircon contains uranium and thorium together in different quantities, usually in the range of less than one weight percent up to several weight percent. Zircon occurs in nature as a crystalline or a partially to fully metamict mineral, depending on age and actinide element concentration, i.e., on radiation damage. These zircon samples have been studied extensively and the results are documented in the literature in terms of radiation damage to the crystal structure and related property changes, e.g., density, hardness, loss of uranium and lead, etc. Thus, a unique suite of natural analogues are available to describe the effect of decay of {sup 239}Pu on zircon's structure and how zircon's physical and chemical properties will be affected over very long periods of time. Actually, the oldest zircon samples known are over 3 billion years old. This period covers the time for decay of {sup 239}Pu (half-life 24,300 yr.) and most of its daughter {sup 235}U
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