Chemical Properties

Introduction

Gemstones have captivated humanity for centuries, not only for their stunning visual appeal but also for the intricate chemical compositions that give rise to their captivating colours and properties. This exploration delves into the chemical aspects of gemstones, categorizing them based on their mineral compositions, revealing their chemical formulas, and understanding the International Mineralogical Association (IMA) symbols associated with each mineral.

Category

Gemstones can be categorized based on their mineral compositions, falling into distinct mineral categories. Here are some prominent categories:

  • Oxide Minerals (e.g. Corundum)
  • Nesosilicates (e.g. Almandine)
  • Phosphate Minerals (e.g. Fluorapatite)
  • Halide Minerals (e.g. Fluorite)
  • Cyclosilicates (e.g. Beryl)
  • Tectosilicates (e.g. Quartz)
  • Sulphide Minerals (e.g. Sphalerite)
  • Native Minerals (e.g. Diamond)

Categories may be further divided into groups or families. For example, Almandine is a Nesosilicate in the Garnet group.

Chemical Formula

The chemical formula of each gemstone represents its elemental composition. Let's delve into the chemical formulas of representative gemstones from each category:

  • Corundum (Oxide Mineral): Al2O3
  • Almandine (Nesosilicate): Fe3Al2(SiO4)3
  • Fluorapatite (Phosphate Mineral): Ca5(PO4)3F
  • Fluorite (Halide Mineral): CaF2
  • Beryl (Cyclosilicate): Be3Al2(SiO3)6
  • Quartz (Tectosilicate): SiO2
  • Sphalerite (Sulphide Mineral): ZnS
  • Diamond (Native Mineral): C

IMA Symbol

The IMA assigns symbols to minerals based on their chemical compositions and crystal structures. Here are the IMA symbols for our examples:

  • Corundum: Crn
  • Almandine: Alm
  • Fluorapatite: Fap
  • Fluorite: Flu
  • Beryl: Ber
  • Quartz: Qz
  • Sphalerite: Sph
  • Diamond: Dia

Conclusion

Understanding these categories, chemical formulas, and IMA symbols provides a systematic approach to identifying and appreciating the diverse world of gemstones based on their chemical compositions and mineral classes. Each gemstone, from the robust oxide of corundum to the intricate cyclosilicate structure of beryl, possesses a unique chemical identity that contributes to its allure in the world of jewellery and mineralogy.