Salagrams can be identified as different forms of the Lord according to Their natural shape and markings. The markings are all natural, as found at the Kali-Gandaki River.
This very auspicious Salagram, identified for me in Nepal, is Laksmi-Narayan. The symptom of a Laksmi-Narayan Salagram are four clear "chakras." There are two, large Chakras on the left side and toward the back, and two small Chakras in the center area.