Able to gather right materials used in making glass (4)

I believe the answer is:

frit

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'materials used in making glass' is the definition.
I can't tell whether this defines the answer.

'able to gather right' is the wordplay.
'able' becomes 'fit' (similar in meaning).
'to gather' means one lot of letters goes inside another.
'right' becomes 'r' (common abbreviation).
'fit' going around 'r' is 'FRIT'.

Can you help me to learn more?

(Other definitions for frit that I've seen before include "terrified" , "Destructive fly" .)

I've seen this clue in The Hindu.

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