There is no such thing as a diamond in geometry. The correct term is a rhombus.

That shape is a kite in geometry.

You ask 100 people what that shape is.

How many are going to say diamond?

Even the people that believe diamonds have all equal sides would say “It’s not a perfect diamond but it is diamond shaped”

Imagine saying “It’s not a perfect square, but it is square shaped” at a rectangle.