China Neodymium And Ferrite Magnets Manufacturer & Supplier 
I do not know if you have found that some magnets will have concave points (small pits) on the surface, and some will line (ferrite white line identification, neodymium magnet red line identification), then what is the meaning of the concave points or lines on the magnet? What does it do?
It's like this magnet pictured below, with a little dimple in the center.
What is the purpose of the dots or pits on the surface of a magnet?
The small pits on the magnet are mainly used to facilitate customers to apply glue. Some magnets have concave points on surface, which are not that large. Their purpose is to facilitate customers to distinguish the usage surface, such as the strong magnetic surface with concave points.
For rare-earth neodymium magnets, since they do not require mold production, they cannot be designed with concave points through molds. Scribing is a relatively low-cost way to help customers differentiate between NS poles, in addition to chamfering, radium N or S, and so on.
Whether it's pits or dents, marking with lines, they have their own unique and wonderful, such as you have other magnet problems can be searched through the site to check the relevant introduction, you can also leave us a message, we will contact you after receiving.
Similar magnets with dots/slots
Round ferrite magnets with dots and chamfers 17.8x7.8mm
N52 Special block bar neodymium magnet with slot in center
Axial multipole ferrite ring magnet with concave point 4 poles 6 poles 30 x 16 x 5 mm
Other common magnet problems;
What does paired magnetization mean?