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→Initial quantities: Parts of the essay were copied from this, obviously.
In the case of carbon dating, it is not the initial quantity that is important, but the initial ratio of C<sup>14</sup> to C<sup>12</sup>, but the same principle otherwise applies.
In the case of carbon dating, it is not the initial quantity that is important, but the initial ratio of C<sup>14</sup> to C<sup>12</sup>, but the same principle otherwise applies.
Recognizing this problem, scientists try to focus on rocks that do not contain the decay product originally. For example, in uranium-lead dating, they use rocks containing [[zircon]] (ZrSiO<sub>4</sub>), though it can be used on other materials, such as [[baddeleyite]].<ref>{{Cite journal|doi=10.2113/104.1.13 |title=SHRIMP baddeleyite and zircon ages for an Umkondo dolerite sill, Nyanga Mountains, Eastern Zimbabwe |year=2001 |first=M.T.D. |last=Wingate |journal=South African Journal of Geology |volume=104|issue=1 |pages=13–22}}</ref> Zircon and baddeleyite incorporate uranium atoms into their crystalline structure as substitutes for [[zirconium]], but strongly reject lead. Zincon has a very high closure temperature, is very chemically inert, and is resistant to mechanical weathering. For these reasons, if a rock strata contains zircon, running a uranium-lead test on a zircon sample will produce a radiometric dating result that is less dependent on the initial quantity problem.
Recognizing this problem, scientists try to focus on rocks that do not contain the decay product originally. For example, in uranium-lead dating, they use rocks containing [[zircon]] (ZrSiO<sub>4</sub>), though it can be used on other materials, such as [[baddeleyite]].<ref>{{Cite journal|doi=10.2113/104.1.13 |title=SHRIMP baddeleyite and zircon ages for an Umkondo dolerite sill, Nyanga Mountains, Eastern Zimbabwe |year=2001 |first=M.T.D. |last=Wingate |journal=South African Journal of Geology |volume=104|issue=1 |pages=13–22}}</ref> Zircon and baddeleyite incorporate uranium atoms into their crystalline structure as substitutes for [[zirconium]], but strongly reject lead. Zircon has a very high closure temperature, is very chemically inert, and is resistant to mechanical weathering. For these reasons, if a rock strata contains zircon, running a uranium-lead test on a zircon sample will produce a radiometric dating result that is less dependent on the initial quantity problem.
=== Rate of decay ===
=== Rate of decay ===