Hard stones are not bad because they are hard but softer stones are easier to use for beginners till they develop a light touch.
Are they smooth in use eg don't feel any of those visible inclusions ? Are they fast cutting ? or slow as a wet week? I've never used or even seen a jade hone. Interesting.

They may not work as scales as a certain amount of flexibility is desirable as the tapered tang works thru its range of travel & well, they are rocks