The geological change of the earth’s surface through weathering and soil erosion over time has created an ideal environment for the formation of minerals. The metamorphic change in combination with adequate amounts of aluminum, chromium (for color), and oxygen in this part of the world, provide good conditions for rubies to form.
What makes the find in Mozambique different, is that the rubies were found in amphibolite type of rock as opposed to being found in marble or basalt which is the most common find. The amphibole type of rubies has a higher iron content than those from marble and lower iron content than the ones from basalt. Rubies get the reddish color from chromium but the color is altered by the amount of iron present, making the make-up and appearance of the rubies different. The deposits from Mozambique offer a new color range to the marketplace that is midway between the lower and higher content of iron in other rubies.