Up to the fourth century, platinum wedding ring was known only in it rough, or crystalline forms. It came in a variety of shapes, the most common being the octahedron. This was a crystal with eight faces, resembling two pyramids joined at their bases.
Extremely subtle color differences can be very important to determine rarity of a diamond stud, but are never a critical factor in beauty.
Remember, all diamonds are not created equal. Two diamonds of equal Carat Weight may vary substantially in price due to their Cut, Colour and Clarity. The carat weight of diamond dealers is a very important determining factor in their value.