This pigment code can refer to genuine Azurite in rock form (or the greener Malachite) which has been ground or the pigment may refer to the synthetic versions. Azurite in its natural form is rare in artist paints. At one time, Natural Pigments made Azurite oil paint, however it is seldom available.
In general PB30 is not well suited to oil binders, and it is reported that this pigment may discolor in oil. This pigment is given a toxicity rating of B, meaning it does have toxicity, so do handle this fascinating pigment with caution. It also contains copper. The Artist's Guide to Health and Safety has more information about the hazards associated with copper pigments.
The fineness of the grind will affect the overall color, so take care not to over-grind it. Gettens describes the larger particles as "deep violet blue in color." While it has a high refractive index and can be beautiful, the larger particles also contribute to the coarse or grainy texture. It is affected by oil, so research this carefully if you use it in oils. The work of Michael Price contains more on this topic. Sometimes Azurite turns black and other times turns green, so care is needed in handling specialty historical pigments such as this one.
