Inorganic Pigments:  Inorganic pigments are often metallic compounds that are insoluble and not reactive to common art mediums.  They tend to have larger particle sizes and usually make opaque paint films, opaque resins or plastics.

Synthetic Organic Pigments:  These are pigments manufactured from petrochemicals and many are structurally similar to common dye families.  They tend to be very intensely colored and offer more range in transparency based on concentration.