sumi; India ink; Chinese ink; ink stick; ink-cake
squid ink; octopus ink
carpenter's inking string
「墨」 has another reading with different meanings.
Mexico
inked marking string
習字には墨を使うのが基本だね。
Using ink is basic for calligraphy.
墨で絵を描くのは難しいけど楽しい。
Drawing with ink is hard but fun.
古い墨は香りがいいと言うよね。
They say old ink smells good.