Alok Jagawat
I believe that only ‘Ratnas’ defined in classics should carry “Swapranavastha” (Self invoked state) and rest of the gemstones are just stones. To energize them one needs proper mantras to invoke their powers which are positioned in dormant condition. This is the same as Idols of Deities need to be “Pranpratishtith” before they are worshipped. But Shalagrams and Dakshinavarti Shankas have their own powers and they are never invoked through Mantras.
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