I tried "palm (tree)" and "breakwater" by now, and "rock" and "ends" are direct quotes from the riddle, which pretty much leaves "island(s)" as the only specific noun/object not yet spoken for. However, generic islands aren't required to have anything that resembles sounds, capes, or rock. Not even generic islands
of Finland, as far as I know. So, one or several
specific island(s)? Fat chance that I know any specific Finnish ones ...
A different sense of "palm"? Palm of a
hand? The fingers certainly make for the "sounds" and "capes", but even if you wear a lot of jewellery, you're not going to have "rock at
every end" (of a finger), unless "rock" is somehow a nickname for a fingernail as well. (And trust me, fingernails are
nowhere near being
that indestructible.)
The shape of whatever
letters that make up one of the words I'm carelessly looking past? The "m" in "palm" would fit the shape, I suppose. But again, a
serif is a serif and
not a "rock".
I was talking about "sand(y)" as well ... sand
is (very small) rocks ... dunes?