According to the K&F concept homepage, the surface treatment for this adapter is "anodized" and that means anodized. Anodised layers are used to improve the appearance and functionality of the surfaces of aluminum materials; With the adapter, the aspect of wear resistance (contact surface to the camera) should play an important role (a black lacquered connection surface would probably start to "dissolve" after a few adaptation processes). 

Could you please update us your full Minolta lens model ?as Minolta has MD MC and AF mount, K&F Concept MD-M4/3 is suitable for: Lens: Minolta MD MC Mount lens(not for Minolta AF mount: KF06.157) Camera: Micro 4/3 (MFT) mount mirrorless camera like Olympus PEN, OM-D series, Panasonic Lumix DMC-G1, G2, G3, G10, GX1, GH1, GH2, GF1, GF2, GF3, GF5, GH4, Panasonic AG-AF100 Mirrorless Digital Cameras, Black Magic Pocket Cinema Camera (BMPCC) 

Please note: our M42 adapter ring could not be suitable for Pentax Takumar Super Takumar Carl Zeiss M42 series（aperture pin does not fully depress, small tabs sticking out), as ours depresses the aperture pin all the way down

 

 

pull back the lever and twist the adapter clockwise (from the back of the lens)