I've got some Indian cents in my collection but I've never understood what the term "four diamonds" refers to. Where is this?
The 4 diamonds refers to the diamonds on the headband. The diamonds are one of the first areas to wear on an IHC so a 4 diamonds IHC is a high grade.
Unfortunatley the graders don't primarily look at these diamonds because the headdress is larger and much more noticeable as we have just seen. Usually you wont see any of the diamonds on VG or less grades and you would only see a band and not think anything of it; but yes they're there.
Ah, OK...I'm almost embarrassed to say that I never noticed that before on mine. Thanks for the info.
This is also an area that can be weakly struck, too. Lack of 4 diamonds doesn't mean necessarily that the coin has wear. Here is a poor photograph of an AU IHC which exhibits 4 diamonds. One of them is a little weak, but you can see it clearly: You will notice that the tips of the feathers are weakly struck on this coin -- this is also a place that sometimes shows weakness along with the diamonds.