Diamonds! (The cutting tool & abrasives kind)

[Stuey]

High quality vs. lower priced.

The particles are different sizes, but the differences in shape are still relevant.

More images via TG:

Higher Quality
Lower Grade

Don't get me wrong, lower-grade particles have their uses, but in most instances the higher quality more faceted diamonds should perform better and last longer.

 

[CAOS]

6" diamond wheel for the bench grinder is THE BEST way to sharpen tungsten, take it over a tungsten grinder any day!

 

[Stuey]

6" diamond wheel for the bench grinder is THE BEST way to sharpen tungsten, take it over a tungsten grinder any day!

I don't ever recall seeing tungsten grinders. Can't imagine how much they must cost!