My Iyengar Father-in-law gifted me with Saligramam during my marriage although he knew well that I wont use it, coz it is a custom to send daughters with Saligramam. The one he gifted us was genuine and was from the deep forests of South America where alone it is believed to be available. The South Americans state that Saligramam is a solidified form of Anaconda saliva which gets solidified following cooling.
This man is obviously trolling, ignore him. They are not solidified saliva, but, they are indeed fossilized remains of some sort of small creature. I believe Shaligrmams used to be found in the river Ghantaki. But, these days, I am told, they can be found only in the upper origins of the river, a good 4 to 5 days trek even from Muktinath shrine. However, along the way to Muktinath from Jomsom locals sell Shaligramam, but the authenticity is questionable, they could be just stones that look like a shaligramam.
Reading this thread it seems to me that there are misconceptions about Shaligramam even from those who seem to venerate it. First off, it is not a pooja item like dhoopam, deepam, pushpam, etc. Shaligramam is the very object of worship. The pooja items are used to do aradhanai to the shaligramam.
The belief is that Sriman Narayana suo moto takes residence in all shaligramam, as opposed to vigrahas wherein he takes residence only upon proper prana pratishta invocation. While Sriman Narayana is said to leave the vighraha if proper aradhana is interrupted even once, not so with shaligramam. Whether or not worship is continued shaligramam is believed to maintain its divinity. The faithful, of course, do not want to see aradhana interrupted even once, so they take the shaligramam even when they travel -- placing it in a bowl of rice is done, but not desirable. If it gets interrupted due to unavoidable reasons, like theettu and no Brahmin male post upanayanam and samasrayanam was available to do the aradhanai, then, when aradhanai is resumed after the teettu is over thirumanjanam (abhishekam) with milk is to be performed. All this means the shaligramam is not just a stone or a fossil to believers, it is God who has made his abode in these objects out of his supposed infinite compassion to make it easy for the sinful souls to worship him.
It is true that proper “madi” needs to be maintained, but then that is not a special requirement only if you do Shaligramam worship, a Brahmin is supposed to maintain “madi” no matter what. This, of course, is impossible unless you have an outhouse separated from the main house where the women can spend their days of rajaswala, if they remain under the same roof, all the great Neptune's ocean cannot get you Madi.
It is true that girl’s parents present shaligramam to the new mappillai, but it is not dowry, and it can never be two shaligramams, the proper count is 1, 4, 6, ....