Task: Class Definition Understanding (ontology: Earth_Environment/SWEET)

Which of the following definitions best describes 'vein'?

A. Constituent is a clast that has no visible contacts with other clasts. Interpreted to be largely or completly immersed in matrix or cement.
B. Constituent crystallized in crystallographic continuity with some other mineral constituent, typically quartz or calcite. In a clastic rock, commonly forms cement as well, but this should be represented using two role attribute links, 'the concept' and cement, because the concept does not necessarily imply cement.
C. Thin sheet of material intruded into the rock. May be hydrothermal, magmatic, or sedimentary.
D. Constituent occurs as a concentric envelope enclosing another constituent. the concept is a non-genetic term.

Answer: Thin sheet of material intruded into the rock. May be hydrothermal, magmatic, or sedimentary.