Two main parts of the intervertebral discs are the outer ring (annulus fibrosus) and the inner gelatinous material. (nucleus pulposus). The outer ring consists of fibrocartilage, while the inner material shows many similarities to the articular hyaline cartilage both in its biochemical and histological appearance.
For this reason, Everything Wedding Rings recommends avoiding black tungsten wedding bands-with one exception. Titanium Kay has recently launched a new tungsten carbide wedding ring design with solid black inlay that is 100% scratch proof. So, if you are looking for a tungsten ring with black inlay features I highly recommend one of the Titanium Kay 2nd Generation rings.
Essentially, the main differentiation between tungsten vs. tungsten carbide is the fact that one is an element and the other an alloy. Tungsten is element 74 on the periodic table and is known for its dark-grey color, high density and hardness. However, tungsten is difficult to work with in its elemental state.