The most common and most likely answer to this crossword clue is the 7 letter word GRANITE
I've seen this crossword clue in The Times
G
R
A
N
I
T
E
More clues leading to the result GRANITE
- Trembling in great rock
- Tangier reconstructed in stone
- Tearing apart rock
- Get moving, engaging Queen for rock
- Dad’s mother, with it, beginning to enjoy rock
- Garnet confused with one type of stone
- Rock played in Tangier
- . Stone fireplace with flipping hot interior
- Tours holiday home filled with smuggled rock
- Carving in great rock
Buddy explains!

The straight part
We know that "rock" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rock = granite.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 GRANITE mean?
GRANITE noun- A group of igneous and plutonic rocks composed primarily of feldspar and quartz. Usually contains one or more dark minerals, which may be mica, pyroxene, or amphibole. Granite is quarried for building stone, road gravel, decorative stone, and tombstones. Common colors are gray, white, pink, and yellow-brown.
- Toughness; the quality of having a thick skin or being rough.