The Hebrew word for "colour" is צבע ("śaba3") and the Hebrew word for "finger" is אצבע ("eśba3").*
Following the Semitic cognates table we can see that Hebrew צ (emphatic s) can correspond to Aramaic ט (emphatic t) and Arabic ظ (emphatic z) or to Aramaic צ and Arabic ص (emphatic s). The first צ derives from a proto-Semitic emphatic voiceless interdental fricative (that doesnt exist any more in the three daughters peeped at here), the second from, you guessed it, an emphatic s.
The Hebrew words for "coin" and "ring" are, respectively, מטבע ("ma6be3a") טבעת (pronounced "6abba3at" with a doubled Bet).
Both words seem to derive from a root טבע (emphatic t, b, Ayin) and I really want them to be loan word from Aramaic טבע which hopefully means "finger" but it might not.
Assuming the first derivation of the roots, the Aramaic and Arabic cognates for צבע and אצבע are quickly determined. The Comprehensive Aramaic Lexicon gives for Aramaic טבע the following meanings
- to seal, to sink
- seal, coin
And for Arabic ظبع (emphatic z, b, Ayin), Google gives me nothing.
Assuming the second derivation, the Aramaic cognates are
- to moisten, to dye
- to cast lots
- colour
- finger
And for Arabic صبع (emphatic s, b, Ayin) Google gives:
- اصبع ("eśba3"): finger
Wunderful. I am not getting anywhere. It didn't work. While the words for "finger" and "colour" appear to derive from the same root which has survived in all three languages, the words for "coin" and "ring" don't seem to be related. The obvious solution is to look at what the root טבע (of coin and ring) actually means, in Hebrew.
- nature
- to drown, to sink (causative)
- to mint, to coin
I have a sinking sensation that coins and rings are simply the products of melting metals and sinking them into a bath. (That means that I drowned with my theory.)
I don't think the translation "nature" has anything to do with this (although it also exists in Arabic as طبيعة (pronounced something like "6abu3a").
So that's it. I cannot connect rings and coins to fingers and colours. But I will always remember the four words as if they belonged together.
*I use ś for an emphatic s and 3 for an Ayin.
**I also use 6 for an emphatic t.