Pyritized fossil from Nepal

My friend brought back the most awesome fossil I have ever seen. I admit fossils are not my thing, but this one I like. It is awesome for many reasons. First, he found it hiking in Nepal on a gap year during his college years. Randomly found it on the trail in one of the most exotic places in the world. He knew I would like it. He knew me well because I have kept it all of these years and all the different places I have lived.

Here are the facts from Alden at about.com.
Many fossils, especially seashells in young rocks, undergo some recrystallization in groundwater. In others their substance is dissolved, leaving open space (a mold) that is refilled with minerals from their surroundings or from underground fluids (forming a cast).
Ammonoids were a very successful order of sea creatures (Ammonoidea) among the cephalopods, related to the octopuses, squids and nautilus.
Paleontologists are careful to distinguish the ammonoids from the ammonites. Ammonoids lived from Early Devonian times until the end of the Cretaceous Period, or from about 400 million to 66 million years ago. Ammonites were a suborder of ammonoid with heavy, ornamented shells that thrived starting in the Jurassic Period, between 200 and 150 million year ago.
Ammonoids have a coiled, chambered shell that lies flat, unlike gastropod shells. The animal lived at the end of the shell in the largest chamber. The ammonites grew as large as a meter across. In the wide, warm seas of the Jurassic and Cretaceous, ammonites diversified into many different species, largely distinguished by the intricate shapes of the suture between their shell chambers. It is suggested that this ornamentation served as an aid to mating with the right species. That would not help the organism survive, but by ensuring reproduction it would keep the species alive.

All the ammonoids died at the end of the Cretaceous in the same mass extinction that killed off the dinosaurs.

Charlotte from the mountain Kingdom website/blog writes,"The nearby Kali Gandaki River is a source of black ammonite fossils, known as saligrams, which are considered holy emblems and worshipped as manifestations of Vishnu."

Maybe this is where he got the fossil. How cool is that for rock enthusiasts to find fossils and have them be sacred too! I read that you are not supposed to break open the fossils. Oh well, I think this one was opened up or found this way.
A writer on ECS Nepal website wrote this about a winter trek."Finding some black ammonites were our third nature quest. We searched for them in the Kali Gandaki river bed but determined that we would have better luck in summer or fall, when the river is fuller and washes new (old) fossils out of its banks. Pilgrims believe the fossils to be a sure sign of Vishnu’s presence. Saligrams are the remnants of an extinct form of cephalopod mollusk with a coiled, flat chambered shell. They lived in and left their remains under the prehistoric Sea of Tethys that existed before the slow continental collision that created the Himalayan uplift that gradually joined the Indian subcontinent to Tibet. According to geologists the Muktinath ammonites date from 140 to 165 million years ago. They are also found in north India and southern Tibet, but those around Muktinath are particularly abundant, well preserved and relatively easy to find.

Before we left the Vishnu Mandir, we saw a stone pillar said to have been erected by Jang Bahadur Rana in the 19th century. Narendra interpreted the inscription on it, to the effect that breaking open the fossils is (or was, in those days) punishable by having your hands cut off! Regardless of his ruling, saligrams are for sale, both whole and broken, at Muktinath and Jomsom, Pokhara and Kathmandu, by two-handed shopkeepers."
Here is more info from gwydire.co.uk website about fossils."In India, ammonites found in the valley of the Gandaki River in Nepal and northern India are called Saligrams. They are considered the direct symbol of Lord Vishnu, as one of Vishnu's avatars (incarnations) was stone (Sri Saligram). Saligrams have markings called 'chakras', resembling the discus held in one of the six hands of the god Vishnu. Vishnu's chakra is a Hindu symbol of absolute completeness, with the eight spokes indicating the eightfold path of deliverance. The radial chakra markings in saligrams are actually the ribs of the ammonites. The stones are kept in temples, monasteries and households as natural symbols of Vishnu and water in which they have been bathed is drunk daily. In addition, saligrams are used in marriages, funerals and house-warmings. If a dying person sips water in which a saligram has been steeped, it is believed that they will be freed from all sins and will reach the heavenly abode of Vishnu. You are not allowed to buy a saligram as they are priceless, although they can be supplied if a donation is made. Saligrams are mentioned in Sanskrit texts dating back to the second century BC. .

This description is from the Oregon University,"Ammonite and nautiloid fossils have been prized from antiquity for their mesmerizing logarithmic spiral. In Hindu religion they are held sacred as saligram (a Nepali example is included here), a reminder of the unfolding of the universe by Lord Vishnu the creator. They are the shells of extinct cephalopods, related to the modern pearly nautilus. Ammonites and nautiloids are prized by paleontologists because they were widespread on the world's oceans, and evolved rapidly. Even with the great array of geological dating techniques now available, geological age can still be determined more accurately by a single ammonite than by geochemical methods. These ammonites and nautiloids are from the recently acquired Retallack collection. Photography by Win McLaughlin, text by Greg Retallack, and web development by Keith Hamm. Images © Museum of Natural and Cultural History."
I also attached a photo of an example from the same website and another saligram from a stock photo.
I can't believe that is what I have had around the house for all these years.
My photos are the two photos with Japanese yen for scale.