Sorry, I'm not sure. It will depend both on the colour of the...

Sorry, I'm not sure. It will depend both on the colour of the material and the propensity of it to break into a fine dust when RC drilled.

If black mafic material created a dust pattern, we would frequently have black dust halo's around RC drilling through Mafic targeting pegmatites. Long mafic intersections will be common in RC drilling but as they are not the target, they aren't reported. I haven't seen black dust halo's so it appears only some materials break apart in a way that creates these dust halo's. Pegmatites can, but I don't know what else does.

So what even is grandiorite?
From google it appears to be defined by more Plagioclase group feldspar than Orthoclase group feldspar. This definition won't help many. Noting Na =Sodium, Ca=Calcium and K=Potassium, they are feldspar's with Sodium, Calcium and Potassium in the chemical formula.

• Plagioclase group of feldspar: NaAlSi₃O₈ (albite) to CaAl₂Si₂O₈ (anorthite). From google some potassium (K) is usually also present
• Orthoclase group of feldspar: KAlSi₃O₈ (Microcline) or K(AlSi₃O₈)

In writing this I hit multiple references to albite and pegmatite/spodumene so I don't think being defined as Complex Grandiorite prevents pegmatites, although it probably alters the likelihood.