My first yixing teapot was a gift from my husband used here as a sort of reference point..
Now I bought more hoping to have 1 for oolong and another for black/pu-erh. In my eBay surfings I ended up buying 3!!!
Avoiding the brand new mass produced merchandise I went for "unresearched" pré owned vintage types, hoping something good will come to me by chance.
1. Very small vivid red shiny number nearly round but hexagonal. No lid
but liked the look of it so much that decided to buy anyway for my desk ornament. Has calligraphy on it. 65ml approx. This is a lot more red than my gifted, bought by hubby from new in London Chinatown. Feels denser, smoother, and makes a lot more ringing high pitched sound when tapped. It's a bit like this compares to my gifted pot clay like a crystal glass ring comparing to normal glass...does it make sense? A bit of research online and now I'm convinced it's handmade.. tooling marks inside bottom radially at the base. Seal mark at bottom teapot and bottom of handle. Feels to touch like a fresh horse chestnut in your hand on an autumn walk...been stoking it all day yesterday 
Now: is it zhuni clay? Can I make tea in it without the lid successfully? Any guesses on age or kiln identity?
2. Second eBay teapot is in dark clay, squat flat top form. 160ml approx
Has toolmarks inside at the bottom and scrapings at the join of the flap top with rest of the body, so handmade?
Has seals inside lid, under on the base and at bottom of the handle. Handle comfortable, a lot thicker at the bottom, with little "bobble" for cantilevering and a simple tooled slashed decoration either side of the bobble. Lid fits very very well, finial is sort of conical (dissapointing uncomfortable and tends to easily slip out of my fingers) bit the whole finial and air hole are executed with care and quite tidy looking. The sound the lid makes is of stone flour mill wheels, not as hollow as terracotta, but still sounding a bit gritty. Visually the clay also seems to have minuscule shiny mica or other mineral flecks, when looking at angle it has shining microscopic inclusions. Ah, also turned out to be unused condition and looked too shiny, so I boiled the teapot- yes it was waxed? So that might give some idea to the people who know about these practices when it was made etc- finding reliable info on that proving difficult. Online research was low on detail so question is: Is it Zini clay? Is it faking to be Zini clay, or maybe some other type altogether. Would it be 1990s of after if it's Zini clay? Any idea on kiln, or any other info.
3. Third teapot I bought on eBay is a monster! Dark/black clay more of a jug than a teapot with pewter or tin metal overlay of dragons. Most definitely for export as unsuitable for Chinese tea style use. Too big, too heavy, hybrid type shape, mixed materials, no spout proper ?!?!?!!! Horror! Marked at bottom in chinese 6 characters in clay and clumsily in Latin alphabet on the metal rim "Hsin Cheng whiehiwei" by someone definitely not familiar with shape of Latin alphabet
So that makes sense since Wheihawei was under British lease from turn of 20cent till 1930? It would make sense to sell stuff to British then and set up exporting outlets in this city particularily, would the item be from that era, or just hawing English writing on it by virtue of being export, earlier or later era? Would it be intended as teapot or kettle- jug? I would keep my water hot in it on table top stove or nearby log burner but would not dare put leaves in it. So maybe that's what it is? Also what is the black clay all about?Well, enough of my ramblings, please help if you have any info or guesses ?! I do like a mystery solving challenge. Time to put a kettle on!