Frankincense is derived from the resin of the bark, which is then distilled. The former, cheaper oil I would think has the most resin remaining in the bottle instead of the more expensive pure oil. That is why the 2nd was more expensive, and stronger scented, it has more of the pure oil in it. The first oil would perhaps be good for many things, particularly mixing with other oils, such as Rose, Lavender or Sandlewood.