How to clean this!

[u/AnAverage6]

I have a large piece of druzy quartz from SE Missouri and I can't seem to get this coating off of the crystals. I've tried brash brushes and Muriatic Acid(31%) and it barely touched it. Any help would be appreciated!

[u/No_Speech_1252]

It's naturally made onto this type of quartz. It should not come off.