Serpentine, a name that incapsulates multiple similarly metamorphic rocks, are an earth color group of stones. They range from translucent green yellow, opaque shades of green, browns, and even black. Serpentines can include inclusions, the smaller usually diff. color areas, that range from purple to dark brown. Serpentine is also known for its slick and waxy feel, similar to that of a snake, which *of course* adds to the name!!
Metaphysically, Serpentine is a very restorative and healing crystal. It works in conjunction with the heart chakra, the energetic center that deals with emotion, healing, and relationships (w/self and others). Serpentine works with the heart chakra, to aid the holder in dealing and working through thoughts and situations that affect the heart chakra (I.e dealing w/a break up, confronting an old friend, remembering a painful situation, etc). Serpentine opens the heart chakra, helping to bring emotions back into balance, and assist in find the root of these emotions and stresses. This allows the holder to confront emotions and stresses head on, and protect them from falling into old, non-serving emotional cycles.
Translating this in the physical realm, this can protect you from individuals that represent old cycles, negative thoughts tied to emotional stress, and assist in confronting and speaking your true emotions to serve self.
Below you can see a few examples of different variations of Serpentine (note the color ranges). We have an Infinite stone (top pic), Lizardite (second pic), and a serpentine with purple inclusions (third pic)