We all heard that diamonds are a girls' best friends...but why?
Some psychologists suggested that they are a girl's best friend because they can help distinguish if a man is Mr. Right, or a Mr Right-Now.
A Mr. Right, who can be a potential good father must possess the ability and the willingness to acquire and accumulate resources, and to invest them in a woman and her children. To demand an expensive gift is a good way to see if a man is capable and willing to invest. Diamonds, in this particular psychological aspect, is expensive but lack of intrinsic value.. They are beautiful but they are not essential. And no men are interested in spending a huge amount of money on something without any intrinsic value, unless they are investing in something.
On that same note, if we look at it from the opposite side, men can also use the same idea to get an idea of whether a woman is in for the long term, or simply for the gifts. Of course, this does not serve as the pure indicator on courtship but one of the good indicators.