The most common and most likely answer to this crossword clue is the 6 letter word CHROME
I've seen this crossword clue in Financial Times
C
H
R
O
M
E
More clues leading to the result CHROME
- Metal business enlists personnel with this writer
- Shiny surface in little church, see
- Plate from church overlooking city
- Brilliant finish in two churches
- Human Resources arrive outside to put a shine on things
- Plating hot starter in ravioli, happen to scoff that
- Decorative finish seen in church, the Catholic one?
- Approach keeping fringes of hair yellow
- Shiny plate given by Switzerland’s capital
- When out of cash, order more shiny stuff
Buddy explains!

The straight part
We know that "Brilliant finish" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case brilliant finish = chrome.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CHROME mean?
CHROME noun- Chromium, when used to plate other metals.
- The basic structural elements used in a graphical user interface, such as window frames and scroll bars, as opposed to the content.
- Handguns (collectively)
- To plate with chrome.
- To treat with a solution of potassium bichromate, as in dyeing.