Summarize this article in one sentence.
Your skin tone is the surface color of your skin and is usually the word you use to describe your skin color (ex. Ivory, light, medium, dark). Your skin's undertone is the color underneath the surface. It is possible to have the same surface skin tone as someone, but different colored undertones. When shopping for a dress you should take both the surface tone and undertone into consideration.  Undertones are typically broken down into three categories: cool (pink, red, or bluish), warm (yellow, peachy, golden), or neutral (a mix of warm and cool). One way to determine your undertone is to look at the color of your veins. Roll up your sleeve and look at the veins on your wrist. Do they look blue or green? If your veins look blue you likely have cool undertones and if they look green you likely have warm undertones. Your eye color can also help determine your undertones. If you have blue, gray, or green eyes you likely have cool undertones. Alternately, if you have brown, hazel, or amber eyes you likely have warmer undertones. Typically people with cool undertones look better in silver jewelry and people with warm undertones look better in gold jewelry. Which do you prefer on your skin tone? Another way to figure out the undertones of your skin is to see how your skin reacts to sun. If you burn easily you likely have cool undertones. If your skin tans in the sun you likely have warm undertones. It is possible to have light skin and warm undertones in the same way that you can have dark skin and cool undertones.   People with fair skin color who burn likely have cool undertones. People with medium/dark skin color who burn and then tan likely also have cool undertones.

Summary:
Analyse your skin's surface tone and undertone. Look at the color of your veins. Take a closer look at the irises of your eyes. Try on silver and gold jewelry. Determine how your skin reacts in the sun.