Cut a Rock Rocks and Rarity

Room Drop Rates from Overhead Boards

Every mining chamber displays a hanging sign titled ROCKS IN THIS ROOM listing the room identifier, node capacity numbers, and drop percentages for available materials. Guide video captures confirm readings for two chambers:

The Room 3 board adds a 15% Rare slot and cuts Common from 50% to 35%. The Nova Prism figure does not move. Frame from the guide video at 2:00.

Room 1 also features an overhead board, but percentage text is blurred and unreadable in available gameplay frames. Rather than inferring numbers, we record Room 1 drop rates as unverified.

The shift from Room 2 to Room 3 reveals how Duality Works scales mining zones. Uncommon drops remain fixed at 50%, while the game reduces Common stones by 15 percentage points to carve out space for Rare drops. Nova Prism stays pegged at 0.1% across both chambers. Reaching these chambers requires clearing cash barriers, detailed in the floor unlocking guide.

The Math Behind the 0.1% Nova Prism Roll

A 0.1% drop rate means each mined rock node carries a 1 in 1,000 chance of yielding a Nova Prism. Because each break is an independent event, you cannot guarantee a drop simply by mining 1,000 rocks.

The math behind cumulative probability clarifies what a 0.1% roll demands. With a drop rate of 0.001, the chance of failing to find a Nova Prism on any individual break is 0.999 (99.9%). The probability of seeing at least one Nova Prism across n independent rock breaks follows the formula:

1 - 0.999^n

To find how many rocks you must break to reach a 50% chance of obtaining at least one Nova Prism, solve for n where the failure rate drops to 0.5:

1 - 0.999^n = 0.5 0.999^n = 0.5 n = ln(0.5) / ln(0.999) n ≈ -0.69315 / -0.0010005 ≈ 692.8

Rounding up gives approximately 693 rock breaks to reach a 50% chance of seeing a Nova Prism drop.

To calculate exact odds for your current mining volume, use the Nova Prism odds calculator.

Mining a raw rock is only the first step. You carry rocks in batches of three (3/3 backpack limit) to processing machines running timers like 12s, 21s, or 24s. Plan station layout using the cutting machine guide to keep machines working during long sessions.

Limited Stone Bundles in the Shop

Players seeking to bypass in-game mining odds can buy stone bundles directly through the developer products store under the LIMITED STONES tab. Four stones are available: Nova Prism, Genesis Monolith, Royal Relic, and Sun Scarab. Each comes in four bundle quantities (1x, 3x, 5x, and 10x), creating 16 total products.

Official developer product documentation categorizes the contents of these bundles as probabilistic items. Prices scale from 49 Robux for a single Nova Prism up to 1,299 Robux for a 10-pack of Sun Scarabs.

Across all four stone types, larger bundles offer slight discounts on a per-unit basis. For example, buying a 10x Nova Prism bundle drops the price per stone from 49 Robux to 44.9 Robux.

Why No Base Stone Value Table Exists

Many players search for tables listing exact cash values or material yields for every cut stone. In Cut a Rock, no public API, developer endpoint, or game documentation provides base sell prices for raw rocks or finished cut materials.

Because official numbers do not exist, publishing cash tables would require fabricating figures. Our site presents only verified data captured from live game interfaces and official endpoints. Track rock value through readings at the [E] Sell Rocks counter rather than unverified estimates.