What type of rocks can be dated to determine the time of crystallization from magma?

Igneous rocks are the correct choice for determining the time of crystallization from magma because they form directly from the cooling and solidification of molten rock, or magma. This process allows geologists to use radiometric dating techniques on the minerals within igneous rocks, typically using isotopes like uranium-lead or potassium-argon. These isotopic ratios can provide precise ages for when the rock was formed, which directly corresponds to the time that the magma cooled and crystallized.

In contrast, sedimentary rocks are formed from the accumulation and compaction of sediments, which may include pieces of older rocks, and they do not form from magma. Thus, their dating generally reflects the age of the sediments rather than the crystallization process.

Metamorphic rocks result from the alteration of existing rocks (either igneous or sedimentary) under pressure and temperature conditions, and their formation age does not necessarily correlate with magma crystallization.

While all rock types can provide valuable information about Earth's history, only igneous rocks can be accurately dated to determine their crystallization age directly linked to the cooling of magma.