Golden box or gold-made box

The sentence which includes the words "A golden box" might well mean a gold painted wooden box.

If you want readers to understand that the box is indeed made of pure gold you could say just that.... PURE GOLD
You could also use the gold assay number.
most gold to make it workable has other metals added to it as pure gold is too soft to be useful.
Gold with other metals added to it is refered to as 12, 18 or 24 carat gold.
Common carats used for gold in bullion, jewellery making and by goldsmiths are:
* 24 carat (millesimal fineness 999)
* 22 carat (millesimal fineness 916)
* 20 carat (millesimal fineness 833)
* 18 carat (millesimal fineness 750)
* 15 carat (millesimal fineness 625)
* 14 carat (millesimal fineness 585)
* 10 carat (millesimal fineness 417)
* 9 carat (millesimal fineness 375)
* 8 carat (millesimal fineness 333)
* 1 carat (millesimal fineness 042)

SO the sentence might read "The jewels were in a 24 carat gold box.

"gold box" is more likely to be one made of gold, tho could also refer to the color, than "golden"box. "box of gold" would be one made of gold, "gold-made box" is not a usage that would be common in English, tho it would probably be understood--it sounds very 15th century.

I think for clarity's sake, one should say something like "a box made of gold".

Thanks