Lesson 5: Uncommon Elements Make Uncommon Gemstones


Step 1: Introduction to Gemology

Lesson 5

Why are some gems more common in nature than others? Gemology teaches us that crystalline gemstones need five things to develop: ingredients, temperature, pressure, time, and space. Let’s take a closer look at that first requirement. Since the principal source of ingredients for gems is the rocky Earth itself, knowing the abundance of the elements that make up the minerals in the Earth’s crust will help us understand why there are common and uncommon gemstones.

The Abundance of Elements In The Earth’s Crust

The following figures are estimated percentages of the Earth’s crust by weight.

The eight most common elements in the crust are:

  • Oxygen (O) 46.4%
  • Silicon (Si) 28.15%
  • Aluminum (Al) 8.23%
  • Iron (Fe) 5.63%
  • Calcium (Ca) 4.15%
  • Sodium (Na) 2.36%
  • Magnesium (Mg) 2.33%
  • Potassium (K) 2.09%

All other elements represent a mere 0.66% of the crust.

From …

Unearth The Secrets Behind The Beauty

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  • How to spot the most unique & valuable characteristics of different gemstones
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Course: Discover Gemology: Fundamentals, Tools & Meanings
Purchase Course: $49
Skill Level: beginnner
Lessons: 48
Time: 480 min