parent rock

The fibre can be separated with great facility, though firmly attached at one end to the parent rock.

Under these circumstances I was curious to observe how far from the parent rock any pebbles could be found.

It contains no substances which have not been derived from the weathering of the parent rock.

Its cleavage sides and edges were fresh and sharp as if it were just broken from its parent rock.

One side was smoothly rounded, but the other was rough and jagged, showing that it had been violently broken from the parent rock.