Light plays a big role in photography. Here are the different examples of light exposure.
The first picture with the three candle holders that look some what like wine glasses have a side-lit lighting.This means that the light is coming from the side and in this particular picture the light is coming from the right side out of a window.
The next picture has the light coming from right above the object or necklace. This light doe not really cast much shadow because it is directly above the object.
The last picture are beads that are being illuminated from underneath. As you can see this causes the bottom part if the beads to be more visible than the upper part