Home / guides / Rarest Rocks in Cut a Rock (Roblox): Nova Prism and Cosmic

Last checked: 2026-11-05 · Game updated: 2026-11-03

Rarest Rocks in Cut a Rock (Roblox): Nova Prism and Cosmic

Cut a Rock on Roblox has one published rare-rock rate. A Room 1 sign, copied by AllThingsHow, puts Nova Prism at 0.1 percent. The sources establish a Nova Prism rate; searches for cosmic do not yet map to a defined rarity in those sources.

Named rocks

The same starter guide says Day 7 pays five limited rocks chosen from four types: Nova Prism, Genesis Monolith, Royal Relic, and Sun Scarab. No sale price or cut time is printed for any of the four. I am not filling those cells.

Common rocks are 85 percent and take 5 seconds. Uncommon rocks are 15 percent and take 30 seconds. Each of those rarities is said to hold five materials. That still leaves most material names unpublished, which is why the Index page stops at seven.

NameWhere it is namedRateSale priceStatus
Nova Prism Room 1 sign and Day 7 pool 0.1% in Room 1 — 1 source
Genesis Monolith Day 7 pool only — — 1 source
Royal Relic Day 7 pool only — — 1 source
Sun Scarab Day 7 pool only — — 1 source

What players mean by cosmic

The cited official description and guides do not define cosmic as a named rarity. Treat searches for cosmic or crystal as exploratory terms rather than a separate confirmed rarity tier. BemmyBlock’s video title says you can buy every 0.1 percent rock; that establishes the creator’s claim, without naming Nova Prism or giving a price.

The official thumbnails depict a purple crystal interior. It is not one of the seven material names. The official description only says rare rocks, rare treasures, and hidden materials.

Official Cut a Rock thumbnail of a crystal geode
Official Cut a Rock thumbnail of a crystal geode
Official Cut a Rock thumbnail of the mine
Official Cut a Rock thumbnail of the mine

Watch

they let you BUY *EVERY* 0.1% ROCK in ROBLOX CUT A ROCK.... BemmyBlock, published 1 November 2026 UTC (31 October in the upload timezone). The title repeats the 0.1 percent rock claim.

Questions

What is the rarest rock in Cut a Rock?

Nova Prism is the only named rock with a rate, 0.1 percent in Room 1. That does not prove it is rarer than rocks in deeper rooms, because those rates are not public.

Is cosmic an official rarity?

No public game text uses it. Its rarity meaning is not established by the cited sources.

Can you buy the 0.1 percent rocks?

A BemmyBlock title says the game lets you buy every 0.1 percent rock. The video is a claim in a title, not a price list, so I am not printing a Robux cost.

Keep going

Index materialsThe named materials that are not these rare rocks. Room 1 ratesThe sign’s three percentages in one table. Beginner routeWhen you are still cutting Commons.

Sources