minecraft java edition - Why can't I mine this block? - Arqade

I've hammered away at the ore block in this screenshot (which I believe is diamond) but I can't break it. I've tried other tools but none have any effect. Can anyone suggest what I'm doing wrong?

Strongholds still limited to only 3 per world : r/Minecraft

Minecraft Is Hiding These Features In Bedrock Edition VS Java Edition

What triggers the Cannot Mine path in the Mine logic block? : r/Desynced

Java Edition 20w22a – Minecraft Wiki

Java Edition missing texture and model uses/Invalid data value blocks – Minecraft Wiki

minecraft java edition technical issues - Blocks aren't showing - Arqade

What triggers the Cannot Mine path in the Mine logic block? : r/Desynced

minecraft java edition - How do you fix massive holes that appear in the ground? - Arqade

Fix Error Blocks and Broken Models in Minecraft

Java Edition 1.17 – Minecraft Wiki

Fix Error Blocks and Broken Models in Minecraft