I've been to London's River Thames, a famous place where it is relatively easy to find ceramics and other relics of the past.
I found something but I have no idea how to distinguish ancient stuff from modern junk.
This is what I found to be interesting:
Is there a way to see if it's something from the past (not the last 100 years)?
Even if I suppose this is junk. It would be nice to find a way to analyze those, for the next time I will visit that place.
Thank you anyway.
It looks like you have part of the bowl of a clay pipe. Probably nineteenth century if I had to guess (based on what I can see of the size and shape of the bowl):
The Museum of London offers an "Object Identification" service for objects found in London.
You can also join the Facebook group River Thames Mudlarking Finds. If you post a picture of your finds there, people will often be wore than willing to help.
One word of caution if you are planning to visit the Thames foreshore in future though. The Port of London Authority have brought in a new licencing scheme. Basically you need a permit even if you are just looking at surface finds - and the permits aren't cheap!
An alternative is to join the Thames Discovery Programme and take advantage of their free (at the time of writing) training opportunities. You can then join them and carry out archaeological work on the foreshore under their licence. (Most of the time you can keep what you find - surface finds on the foreshore are unstratified and so provide little additional information. However, there are exceptions - especially if the find is designated as being one of National Importance!).
If you are in the UK, but not in London, similar opportunities are available nationwide through the new CITiZAN (Coastal and Intertidal Zone Archaeological Network) Programme.
Have you never watched "Time Team" on BBC? The reason for all those painstakingly small brush strokes in a dig site is because for most artifacts, including ceramics, the only way to identify age is by the nearby presence of organic (or other more easily dated) material. There are some techniques for dating pottery shards, if you have enough money, but basically once you picked up that shard with your hands you abandoned all hope of accurately and reliably dating it.
The lone exception is if you discovered a large enough piece with a well known maker's mark; which this piece appears not to have.
I would try contacting the University College of London's Institute of Archeology. They likely have experts in identifying ceramics who might be able to help.
Nope. There isn't. Since there is no competition with "China from China" the best way to value ceramics both yesterday and today is by weight(lighter the better), color (blues and bright whites in contrast), hardness (thin but strong), form (simple plate or a vase for holding water implying enormous strength), etc
The only way a laymen might pick up a fraud from "the real deal" is by detecting the difference between hand thrown and machine made as hand made will have readily apparent imperfections whereas that which is machine made and hardened...and "glossed"(spray painted instead of glazed) are the only dead giveaways I am aware of.
