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Geologica completely replaces vanilla stone with custom types of rock. These support all of the typical stone-derived blocks, such as cobblestone, stone bricks, cobble/brick slabs, cobble/brick walls, and, in some cases, cobble/brick stairs. Existing recipes expecting stone, cobblestone or stone bricks as an ingredient are automatically ore-dictified to support the new types (even those recipes added by mods). There are furnace recipes to convert cobblestone to stone. A major gameplay mechanic is that rocks have specific hardness values and pickaxe mining levels. The durability of stone tools depends on the hardness of the rock used in their construction.

Hardness Mechanic

There are four different hardness levels (default values in parentheses): weak (1.0), medium (2.0), strong (3.0) and very strong (4.0).  By default, medium stone has the same hardness as vanilla cobblestone, and very strong stone is twice as hard. Each hardness level corresponds to a pickaxe harvest level, such that a wooden pickaxe is only capable of harvesting weak stone, a stone pickaxe is required for harvesting medium and strong stone, and iron is necessary for very strong stone.

Shattering a weak stone yields rubble, which behaves much like gravel (except does not yield flint).  This models the fact that many types of stone, usually sedimentary, are not well suited for building. Medium and strong stone will yield particular types of cobblestone upon harvesting. These can be smelted back to solid stone. Very strong stone is harvested as intact stone.

Stone tools can be constructed from either rubble or cobblestone. The durability depends on the strength of the original stone. Weak stone (rubble) yields a pickaxe with 25% the durability of a vanilla stone pickaxe, while medium cobblestone yields 50% durability, and strong yields 100% (i.e., unchanged).

Hardness Value (default) Tool durability (of stone)
Weak 1.0 25%
Medium 2.0 (= vanilla cobble) 50%
Strong 3.0 100%
V.Strong 4.0 100% (*)
  • Extra processing needed to obtain cobblestone variant of very strong stone.

World Generation

There are several basic types of rock formation, which generate depending on the geome.

Rock formation types
Formation Description
Primary Stratum Primary layer of the crust
Localized Stratum Horizontal deposit of limited extent
Intrusion Igneous veins and localized strata, higher than usual

Rock Types

This section lists all of the rock types, with their hardness and how they are distributed. We begin with the igneous rocks, which are either intrusive or extrusive. The intrusives (the first five in the table below) formed from magma that cooled beneath the surface. The extrusives (the latter four in the table) formed from lava that cooled on the surface, and so are more associated with volcanic activity. Granite is the dominant igneous rock in the continental crust.

Igneous rock hardness and distribution
Rock Hard Distribution
Diorite V.Strong Bottom continental, above gabbro felsic; intrusion
Gabbro V.Strong Bottom felsic, oceanic; intrusion
Peridotite V.Strong Intrusion
Granite Strong Above diorite continental, felsic; domes
Pegmatite Strong Veins in granite
Carbonatite Weak Rare, short, vertical veins; continental
Andesite Strong Above granite felsic
Basalt Strong Above gabbro oceanic; shield volcano; islands
Rhyolite Strong

Top felsic

The sedimentary rocks listed below are generally located near the surface, where they were formed through the hardening of sediment that settled to the bottom of lakes, rivers and oceans. Mudstone is the dominant sedimentary rock on the continents, and limestone becomes quite common under the sea, as well as the hills due to its resistance to erosion. Sandstone is more resistant than limestone, and so is found at the top of hills and some mountains. A special type of sedimentary rock is coal, a common fuel source. Along with sandstone, coal is represented by the vanilla block and has all of the same uses.

Sedimentary rock hardness and distribution
Rock Hard Distribution
Breccia Weak Localized continental, folded
Claystone Weak Localized continental, folded, oceanic
Conglomerate Weak Localized continental, folded
Mudstone Weak Primary continental, folded; localized oceanic
Limestone Medium

Localized continental, folded; primary oceanic, hills

Sandstone - Localized continental, folded, oceanic; primary hills
Coal - Large beds, twice as common in swamps

Metamorphic rocks are derived from sedimentary and, sometimes, igneous rock and are generally found as localized strata in the bottom reaches of the sedimentary layers. Their hardness varies, and they can be quite durable. The strongest, such as quartzite and gneiss, are often cap the peaks of non-volcanic mountains.

Metamorphic rock hardness and distribution
Rock Hard Distribution
Slate Medium Continental
Schist Medium Below slate; felsic mountains, oceanic
Skarn Medium Continental, oceanic
Gneiss Strong Below schist; peaks of alps (BoP)
Greenschist Strong Near bedrock
Marble Strong Continental
Hornfels V.Strong Continental
Quartzite V.Strong Continental; mountain peaks
Serpentinite Medium Veins throughout crust