Question

Which word in this excerpt from act II, scene IV, of Shakespeare's Twelfth Night is a reference to a color-changing gemstone, hinting at Orsino's inconsistent nature?
CLOWN: Now, the [melancholy] god protect thee; and the 
tailor make thy[ doublet] of changeable[ taffeta,] for 
thy mind is a very [opal.] I would have men of such
[constancy] put to sea, that their business might be 
every thing and their intent every where; for that's 
it that always makes a good voyage of nothing. Farewell..

Answer 1

Word in this excerpt from Act II, scene IV, of Shakespeare's Twelfth Night which is a reference to a color-changing gemstone, hinting at Orsino's inconsistent nature is 'opal'.

Feste when compares Orsino to taffeta, he suggests that Orsino should display what he is in person through his clothing. Feste expresses his view that Orsino is "changeable" and that "thy mind is a very [opal.]" Therefore, he concludes that Orsino is someone that he cannot be relied upon just like an opal, which looks in different colors from different angles. Hence as an opal, Orsino change is perspective with what encounters him. As Orsino has no directions, therefore, Feste suggests his life be well suited on the sea "put to sea" as it will takin his "intent" wherever it would.

Answer 2

Based on the given excerpt above, the word in the excerpt from act II, scene IV, of Shakespeare's Twelfth Night that is a reference to a color-changing gemstone, hinting at Orsino's inconsistent nature is the word OPAL. Hope this helps.