Precious Stones
A native iOS app that renders rough stones live with a custom Metal material, so light moves through them as they turn. Designed and built end to end, renderer first.
Why I built it
A photo of a rough stone loses the thing you would buy it for: the light moving through it as it turns. I wanted to know how far one designer can take real-time rendering on a phone without an engineer, and whether that light could carry the whole interface.
What it is
A calm collection on a white page you can scroll forever. Tap a stone and it lifts forward with its notes, drag to rotate it, pull down to put it back. Nothing else on the screen competes with the stone.
How it works
SwiftUI for the app and a custom Metal material for the stones. Each one is a reshaped icosphere with noise, striations and chip planes, lit by a studio HDRI, and the renderer holds a steady frame rate with several stones live at once. I built the renderer first and the interface around it; the clip on the home page is the real build driven by a scripted demo.
What I learned
Build the hard part first. Once the renderer existed, the interface almost designed itself, because every decision was about staying out of the stone’s way. I run teams the same way now: prove the riskiest part before anyone designs around it.