Diamond with Mobile Green Diamond Inclusion
Diamond inclusions are relatively common guests in diamond crystals. They generally go unnoticed as the refractive index of the host and guest are the same. So it is often the case that the only visual clues to such an inclusion lie in the interface between the host and guest, where the slight mismatch traps fluids from the growth environment and leaves a delicate optical irregularity with the appearance of a ghost-like framework of diamond. Inclusions like this can be further explored by examining stones in polarized light, which often reveals significant strain around the guest diamond.
One of the most interesting examples of a diamond inclusion in diamond the authors have encountered is a 0.87 ct sawn crystal section containing a negative crystal cavity (figure 1) that is open at the surface. Inside is a tiny green octahedral diamond crystal that is free to rattle around but too large to exit through the opening at the surface (figure 2).
To see the green diamond inclusion moving inside the negative crystal contained in the host diamond, watch this video:
Presumably this diamond inclusion was completely encased in its diamond host, but dissolution occurred as the host made its way to the earth’s surface, causing the interface between the two crystals to widen until the small entrapped crystal was liberated enough to become mobile (J.I. Koivula, The MicroWorld of Diamonds, Gemworld International, Northbrook, Illinois, 2000, 157 pp.). Subsequently, the diamond must have been exposed to fluids carrying radioactive materials that entered through the small opening, causing green radiation staining of the negative crystal and guest diamond inclusion. While mobile diamond inclusions in diamond are always remarkable (see the Lab Note on the “Matryoshka” diamond in this issue), this example is the only one the authors have observed of a mobile green diamond inclusion trapped in a colorless diamond.
