📚 IGCSE Edexcel Science: Rocks and Minerals – Exam Points Mastery | IGCSE Edexcel 科学：岩石与矿物 考点精讲
Welcome to this comprehensive revision guide on Rocks and Minerals for IGCSE Edexcel Science. Whether you are studying single or combined sciences, understanding the Earth's lithosphere is crucial. This article breaks down key concepts, definitions, rock types, the rock cycle, chemical weathering, and exam tips in a bilingual format to strengthen your knowledge and examination skills.
欢迎阅读这份针对 IGCSE Edexcel 科学的岩石与矿物综合复习指南。无论你是在学习单科科学还是综合科学，理解地球岩石圈的内容都至关重要。本文以双语形式分解关键概念、定义、岩石类型、岩石循环、化学风化以及考试技巧，以强化你的知识和应考能力。
1. What is a Mineral? | 什么是矿物？
A mineral is a naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition. Minerals are the building blocks of rocks. Examples include quartz (SiO₂), feldspar, and calcite (CaCO₃). Each mineral has unique physical properties that allow geologists to identify them.
矿物是天然形成的无机固体，具有晶体结构和固定的化学成分。矿物是岩石的组成部分。常见的例子包括石英（SiO₂）、长石和方解石（CaCO₃）。每种矿物都具有独特的物理性质，可供地质学家用来鉴定。
2. Key Properties of Minerals | 矿物的关键性质
Geologists use several properties to identify minerals: hardness (Mohs scale), colour, streak (colour of the powder), lustre (metallic or non-metallic), cleavage and fracture, and density. For example, quartz has a hardness of 7 and a vitreous lustre, while calcite fizzes with dilute acid.
地质学家利用多种性质来鉴定矿物：硬度（莫氏硬度计）、颜色、条痕（粉末颜色）、光泽（金属或非金属光泽）、解理与断口以及密度。例如，石英的硬度为 7，具玻璃光泽；而方解石遇稀酸会起泡。
A quick reference table is useful for your revision:
一个快速参考表对你的复习很有帮助：
| Property / 性质 | Description / 描述 | Example / 示例 |
|---|---|---|
| Hardness | Resistance to scratching; Mohs scale 1–10 | Talc = 1, Diamond = 10 |
| Streak | Colour of powdered mineral | Haematite: red-brown streak |
| Lustre | Way light reflects from surface | Galena: metallic lustre |
| Cleavage | Breakage along flat planes | Mica: perfect cleavage |
3. Igneous Rocks: Formation and Types | 火成岩：形成与类型
Igneous rocks form from the cooling and solidification of magma or lava. They are classified into intrusive (plutonic) rocks, which cool slowly underground forming large crystals, and extrusive (volcanic) rocks, which cool quickly on the surface producing small crystals or glassy textures. Granite is a common intrusive rock; basalt is a typical extrusive rock.
火成岩由岩浆或熔岩冷却凝固形成。它们可分为侵入岩（深成岩），其在地下缓慢冷却形成大晶体；以及喷出岩（火山岩），其在地表快速冷却，产生小晶体或玻璃质结构。花岗岩是常见的侵入岩，玄武岩是典型的喷出岩。
t cooling → fine crystals or no crystals (e.g. obsidian). This is a classic exam question.
记住冷却速度与晶体大小之间的关系：缓慢冷却 → 大晶体（如花岗岩）；快速冷却 → 小晶体或无晶体（如黑曜石）。这是一个经典的考试问题。
4. Sedimentary Rocks: Processes and Examples | 沉积岩：过程与例子
Sedimentary rocks are formed through the accumulation and lithification of sediments. Four key processes are: weathering (breaking down of pre-existing rocks), erosion and transport (by water, wind, ice), deposition, and finally compaction and cementation. Sedimentary rocks often contain fossils and show layers (strata).
沉积岩通过沉积物的积累和成岩作用形成。四个关键过程是：风化（破碎原有岩石）、侵蚀和搬运（由水、风、冰进行）、沉积，最后是压实和胶结。沉积岩常含有化石并呈现层理（地层）。
Common examples include sandstone (sand grains cemented together), limestone (mainly CaCO₃ from shells or chemical precipitation), and shale (compacted clay). Limestone is especially important in IGCSE chemistry because it reacts with acid and decomposes upon heating.
常见的例子包括砂岩（砂粒胶结而成）、石灰岩（主要由来自贝壳或化学沉淀的 CaCO₃ 组成）和页岩（压实的粘土）。石灰岩在 IGCSE 化学中尤其重要，因为它能与酸反应并遇热分解。
5. Metamorphic Rocks: Changes Under Heat and Pressure | 变质岩：热与压力下的变化
Metamorphic rocks form when existing rocks are subjected to high heat and/or pressure, causing physical and chemical changes without melting. This process can produce new minerals and re‑align crystal structures. Marble (from limestone) and quartzite (from sandstone) are non‑foliated metamorphic rocks. Slate (from shale) and schist are foliated, displaying banding or layered appearance.
变质岩是当原有岩石受到高温和/或高压作用时形成的，这会导致物理和化学变化但不熔化。这一过程能生成新矿物并重新排列晶体结构。大理石（由石灰岩变质而来）和石英岩（由砂岩变质而来）是无叶理的变质岩。板岩（由页岩变质而来）和片岩是具叶理的，呈现条带状或层状外观。
and building), shale → slate (used for roofing). Always link parent rock to daughter rock.
需要记住的关键例子：石灰岩 → 大理石（用于雕塑和建筑），页岩 → 板岩（用于屋顶）。务必将母岩与子岩联系起来。
6. The Rock Cycle | 岩石循环
The rock cycle is a continuous process that describes how rocks change from one type to another over geological time. Igneous rocks can be weathered into sediments, which form sedimentary rocks; sedimentary rocks can be metamorphosed; metamorphic rocks can melt to form magma, which then cools to igneous rocks. All pathways are possible.
岩石循环是一个持续的过程，描述了在地质时间尺度上岩石如何从一种类型转变为另一种。火成岩可风化成沉积物，进而形成沉积岩；沉积岩可变质；变质岩可熔融形成岩浆，随后冷却成火成岩。所有转变路径都可能发生。
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