Is anything harder than a diamond?

Trying to ID this. Harder than quartz but not a diamond? : r/rockhounds

Opinion: Harder than diamond: have scientists really found something tougher than nature's invincible material?

Hobbs Sisters Explore The Realities of Love & Marriage In New Single, Harder Than A Diamond - 117 Entertainment Group

Asteroid impacts on Earth make structurally bizarre diamonds

Is Cubic Boron Nitride (c-BN) Harder Than Diamond? - Triatic, Inc.

Diamond no longer nature's hardest material

Superhard Materials What's Harder Than Diamond?

Let's learn about diamond

New Synthetic Diamond Is Harder Than Nearly All Found in Nature - Ochen