I have two drop spindles for sale, made by me with ceramic whorls (thrown on the wheel) and hardwood shafts. Each spindle has a hook carved in each end so they can be used as top or bottom whorl (my wife who spins says that they work better as bottom whorl they way they're set up now).
My wife has been spinning with a similar spindle for the past year, and gave both of these her stamp of approval tonight.
I did a bit of research before making these, and the whorl shapes are both appropriate for early period impressions. Ceramic did not appear to be the most common whorl material in the reports I read (there were more made from stone and bone), but ceramic whorls were found. Being ceramic they are, of course, breakable if they're dropped onto a hard floor.
Here's a photo of the two spindles:

And the details for each:
Spindle 1.
Weight: 26g / 0.917oz (light-medium weight yarn)
Whorl: This whorl is made from clay dug by my ceramics instructor in PA and processed by her students. It's been burnished and low-fired, and has a rich orange-brown color.
Spindle 2.
Weight: 34g / 1.19oz (good for spinning medium weight yarns)
Whorl: made from the same PA clay as #2.
My wife likes this one best.
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In action!

I'm asking $15/ea + $5 s/h to the continental US, and I like paypal.
PM or email (alric at drentha dot com) if interested.
Thanks!