Taimane is the name of a famous 'ukulele artist of (mixed) Samoan descent. Her web page states that taimane "translates to diamond from Samoan" (and the Wikipedia page repeats this). I got to wondering: Is this really a Samoan word? Isn't it likely to be a loanword from English?
First, I note that no Wikipedia nor Wiktionary for any of the Polynesian languages have any entries for diamond - for whatever that's worth. As a double-check, I also tried searching the Samoan and Maori Wikipedias and Wiktionaries for "taimana" and variants thereof, with no hits.
Google translate certainly maps "diamond" to "taimane" for Samoan, "taimana" for Maori, and "daimana" for Hawaiian. Tahitian uses simply "diamond".
So if this word is borrowed from English, we should be able to establish that it is of recent provenance.
Helpfully, there is a Samoan language Bible on Archive.org. It was published in 1887.
BibleGateway doesn't have a Samoan version, but does have a Maori
version. (Unfortunately, there is no information about it, including
publication date.)
The word "diamond" does not occur often in the Bible. A couple places are:
Jeremiah 17:1(a):
The sin of Judah is written with a pen of iron, and with the point of a diamond ...
Ezekiel 28:13(b):
... the sardius, topaz, and the diamond, the beryl, the onyx, and the jasper, the sapphire, the emerald, and the carbuncle ...
These are as found in the King James Version (KJV). The Revised Standard Version (RSV) has "diamond" in the first passage, but "chrysolite" in the second. Young's Literal Translation (YLT) is similar to the KJV: it likewise has "diamond", but has "ruby" in place of "sardius".
Here are the corresponding phrases in the (modern?) Maori version:
Jeremiah 17:1(a):
Kua oti te hara o Hura te tuhituhi ki te pene rino, ki te mata hoki o te taimana ...
Ezekiel 28:13(b):
... ko te harariu, ko te
topaha, ko te taimana, ko te perira, ko te onika, ko te hahapa, ko te
hapaira, ko te emerara, ko te kapakara ...
Clearly "taimana" is the word which the translator used for "diamond".
Now what about the 1887 Samoan translation?
Jeremiah 17:1(a):
Ua tusia le agasala a Iuta i le peni uamea ma le mata o le samira ...
Google translates this to:
The sin of Judah is written with a pen of iron and with the point of a samarium ...
Ezekiel 28:13(b):
... o le salikea, ma le topasi, ma le ialoma, ma le tasesa, ma le soama, ma le iasepi, ma le safaira, ma le nofeka, ma le pereketa ...
Google translates this to:
... the sardius, the topaz, the jasper, the onyx, the beryl, the onyx, the jasper, the sapphire, the onyx, and the beryl ...
Google seems to struggle with some of those words, punting, in several cases, to "beryl" and "onyx".
Even so, none of the words in the original even remotely resemble "taimane".
Therefore, I believe it is reasonable to conclude that "taimana" was introduced into Maori and certain other Polynesian languages, including Samoan, in the modern period.