> Just a comment on 'amber'. Both 'amber' words (amber proper and
ambergris, or the sperm whale secretion) are the same. They are derived
from Mediaeval Latin ambar < Arabic 'anbar 'ambergris', hence
'brownish-yellow'. The technical Polish word is bursztyn (a German
loan), but the mineral is also known as jantar (ultimately an East
Baltic word, cf. Lithuanian gintaras, Latvian dzitars). I've no idea if
an etymology has been proposed for it. The Old Prussian word was still
different, gli:sis, cf. Latin gle:sum (in Tacitus' report of the
Aestii). The etymology of Greek e:lektron is obscure (at least to me at
the moment), but it looks IE, with the 'instrument' suffix *-trom.
Two notes.
1. The Baltic origin of 'jantar' has not been proven so far. In fact,
the only proof is that it was the traditional Balts trade (still not
proven that Tacitus' Aestii were the Balts, BTW). It's not surprising
that you have no idea about it's etymology - all the attempts to give
the BALTIC one have failed. Considering the fact that Lithuanian
dialects have 'jintaras/jentaras' along with 'gintaras', as well as the
fact that the formant -tar- is a very typical one for the Indo-Aryan
languages (I mean those to the North of the Black sea, their presence
is attested by hydronymy), we can suppose that Lithuanian and Latvian
words were borrowed from Eastern Slavic (cf. Russian jantar'), which
with a help of some mediators eventually borrowed it from the speakers
of some Indo-Aryan language.
2. Tacitus' 'gle:sum' is not Latin, it's rather a Latinised German
word, a cognate of 'glass' and one of the many descendants of PIE root
*gel- 'something round and/or smooth and glossy'