1,250°C Olivine Drop • Pyroxene Reaction Rims • Oscillatory Plagioclase Zoning • Final 650°C Granite Quartz (60FPS)
Hot 1,250°C mantle melt never freezes into one uniform block. Dense green Olivine & Ca-Plagioclase crystallize first and sink, steadily stripping Magnesium, Iron, and Calcium out of the remaining magma.
As remaining melt grows richer in Silicon and Oxygen, crystal architecture evolves smoothly upward from isolated SiO4 islands (Olivine) -> Single Chains (Pyroxene) -> Double Chains (Amphibole) -> Sheets (Mica) -> 3D Frameworks (Feldspar + Quartz).
High-temperature minerals packed with loose Mg/Fe cations (Olivine, Augite) rust swiftly in rain—while last-formed, tightly welded pure Quartz resists billions of years of coastal waves as pure white sand.
At Carnegie's Geophysical Laboratory, N.L. Bowen melted artificial silicate rocks inside platinum crucibles across 600-1,500°C and quenched them—revealing the iconic Y-shaped Reaction Series taught in every geology department worldwide.
Once 98% of a granite magma freezes into Feldspar and Quartz, stray 'misfit' ions too large or small to fit common rocks—Lithium, Beryllium, Boron, Cesium, Tantalum, plus superheated H2O—concentrate at ~600°C to grow meter-long Tourmaline, Emerald/Aquamarine, and Spodumene!
Apollo lunar basalts reveal textbook Olivine, Pyroxene, and Anorthite—yet zero Hornblende, Biotite, or true Granites—because the anhydrous Moon lacked dissolved H2O vapor needed to build OH-bearing amphiboles and lower solidus temps!
Samuel Goldich proved in 1938 that minerals rust at Earth's surface in the EXACT order they formed: unstable Olivine dissolves first into iron-clay soil, while tough 3D-bonded residual Quartz outlasts mountains to blanket white tropical beaches.
| Mineral / Control | Chemistry / System | Property | Diagnostic Signal | Classic Source |
|---|---|---|---|---|
| Forsterite Olivine | (Mg,Fe)2SiO4 | Isolated SiO4 | 1,150 - 1,250°C (1st Out) | Sinks first; reacts w/ free silica |
| Augite Pyroxene | Ca(Mg,Fe)Si2O6 | Single Chain (SiO3) | 950 - 1,100°C | 90° cleavage; dry/wet basalt |
| Hornblende Amphibole | Hydrous Ca-Mg-Fe-Si | Double Chain + OH | 780 - 920°C (Needs H2O!) | 56°/124° diamond prisms; wet arcs |
| Biotite Black Mica | K(Mg,Fe)3AlSi3O10(OH)2 | 2D Sheet + OH | 720 - 820°C | Flexible dark books; last Fe/Mg sink |
| Plagioclase Series | CaAl2Si2O8 -> NaAlSi3O8 | 3D Framework | 1,200 -> 700°C Continuous | Parallel twin striations; zoning rings |
| Orthoclase & Quartz | KAlSi3O8 + SiO2 | 3D Tectosilicate | 600 - 740°C (Last Out!) | Pink granite + final glassy beach sand |
Because Olivine ((Mg,Fe)2SiO4) is undersaturated in silica. If excess silica liquid surrounds hot Olivine crystals during cooling, it chemically reacts with the Olivine to convert its rims into Enstatite Pyroxene (`Mg2SiO4 + SiO2 -> 2 MgSiO3`), exhausting Olivine long before pure Quartz can crystallize.
On the left Discontinuous branch, cooling forces sudden structural leaps as tetrahedra link closer: Isolated islands (Olivine) -> Single chains (Pyroxene) -> Double chains (Amphibole) -> Sheets (Biotite). On the right Continuous branch, Plagioclase keeps its exact 3D framework while smoothly trading Ca+Al for Na+Si.
Quartz forms dead last with 100% shared strong covalent Si-O-Si 3D corner bonds and zero easily leached metal cations. Olivine's isolated SiO4 islands sit held together only by ionic Mg2+/Fe2+ bonds that rainwater rapidly hydrolyzes.
As ordinary granite minerals freeze, misfit trace elements like Beryllium, Boron, Lithium, Fluorine, and water concentrate in the tiny remaining 600°C pocket melt—lowering viscosity dramatically so ions zip across fluid pockets to grow giant flawless gem prisms.