Study of mineral inclusions and CL images of gem quality natural diamonds — Suggestions to comprehension of growth history of diamonds —

Abstract

Mineral inclusions  and cathodoluminescence images of gem quality diamonds are studied. Most of gem quality diamonds are P-type, which have been presumably grown in ultramafic magma in the upper mantle.
Contrary to this, many of E-type diamonds, which are commonly seen in pink diamonds, show Mixed-habit-Growth that suggests they have been generated as micro-diamonds in the ultrahigh-pressure metamorphic rocks in the subduction zone, and then they have sunk into deeper to grow further in ultramafic magma.