One of the most important of the four C’s in jewelry selection is color. Particularly for diamonds, the color can vastly affect the finished product and make your diamond sink or swim with its success or failure as an engagement ring, wedding present, or other such token. For diamonds in particular a thing like color is important. What you strive for in your diamond collar is no color and if you've got a diamond that is a little yellow that's one thing but if you got a diamond that is discolored with brown splotches all over the place it will definitely drag down the overall appeal of the diamond and make the value of the stone that much less.
When talking about diamonds many jewelers have what's known as a diamond color chart. This will show in flats two-dimensional fashion what the diamonds color may look like and how it will change depending upon what the color of the diamond you have is. They should be able to point out the stone you are looking to purchase on the chart and where it falls; if for whatever reason you don't agree with your jeweler's analysis of where the diamond falls, ask to see something better. If your jeweler refuses or is it a sin and you can be sure that they are a non-reputable source for your diamond selection and you should go elsewhere.
Diamond color scale goes from no color to light-yellow to yellow to light green to brown. In broad strokes as pretty well it and these are the figures you have to contend with. While it may not seem pleasant always, that's the truth. You should not purchase a diamond if you are still not comfortable with understanding how color affects a diamond and you should certainly do more research. Especially if your jeweler is just trying to pass off a stone on you that you're not absolutely sure you want to buy, you should not do that. There are a number of reputable retailers who will take the time with you to help you understand what it is you're buying and will gladly give you the space to consider the purchase as is a large one.
With diamonds of four C's exist across a fairly definable spectrum. Cut, clarity, color, and carat; if there are any questions about this or how these conclusions are reached, you should certainly ask more questions. That's really all you can do is just keep asking questions until you are satisfied and if you're not ever satisfied then you should not be buying a diamond. This is a ring your lady will wear for hopefully the rest of her life and this is something that you need to cherish as much as she does.