You can use either nitric acid or hydrochloric acid to dissolve  rock salts. Usually boiling of the  dilute acid solution (6N) helps to dissolve the rock salts.The key is the concentration of rock salts .If it is too concentrate the dissolution becomes too difficult.

In the presence of silicates you have to add some HF, in order to dissolve the silicates to access metal iones enclosed in the silcate matrix.

You can also use mixture od nitric and hydrochloric acids in microwave system.

Dear Ahmed

My suggestion do Total digestion method  for dissolving the samples. Combining Aqua regia + HF solutions.

Best regard's

Zolhizir bin Daud

I thank you very much, but I am asking about  steps for dissolving and Digestion , I mean, Clear method steps 1,2,3,.....etc and how many ml of Acids and how much time ? 

Thank you very much Dr Khan 

By  grinding your rock, you can perform an alkaline fusion into lithium metaborate 98.5%/ lithium bromide 1.5% flux. We already use this technic on geological sample for rare element.

0.1g of grind powder in 1g of flux. Perform the fusion into platinum crucible with a fluxer (Claisse Corp.) and recolt it into PFA  beaker with 100ml of acid. (10%HNO3/0.5%HCL)

We dilute 60 times to reduce the salt into the ICP-MS.