The effect of heat treatment on the inclusion in demantoid
The issue of heat treatment demantoid sometimes becomes important. Unfortunately, it is very difficult to determine. But there are some signs indicating heating stone
This is viewing hollow channel or fibers under good magnification. Under the influence of high temperature fibers or channels are often torn. This is quite clearly seen!
However, now is used very neat (low-temperature) process (sometimes under vacuum), then it is impossible to determine the existence of treatment
In the photos I tried to show what it looks like. For example, taken two stones, one heat-treated (photo 1) and the other without treatment (Photo 3.4)
Photo 1. Inclusion of hollow channels demantoids. Red area indicates a detailed view. Increasing 20x
The presence of these discontinuities allows us to make an indirect conclusion about the heat treatment.
In the following photos are clearly visible fiber bissolita they smooth. In contrast to channel, fiber bissolite not "crushed". The "tail" has a correct form
Photo 3. Bissolit tail in the form of "sun". Increasing 40X
This form inclusions often found in stones in Tagil (river Bobrovka). Often, the fibers have a growth center. For Poldnevayaerea and Karkodin mine "Sun" is not typical
On the next photo shows the an interesting inclusion. It is GLI or other mineral. To determine the need to a larger increase
Photo 4. Unspecified mineral (?) In Tagil demantoids. Presence GLI or mineral confirms the absence of traces of heat.
These features can be used to identify a heat treatment for demantoid of Poldnevaya or Karkodin mine
Important! reliable official methodology for determining the heat treatment does not exist