An in depth article which delves into the inner world of Tsavorite gemstones. examining the different types of inclusions typically seen in this gem type and also some not so typical. Professional Micro-photography with GIA microscope and microscope camera.
Tsavorite is an ancient gemstone formed in a Neoproterozoic metamorphic event. As such, it often contains a myriad of interesting inclusions.
This article aims to catalogue some of the more usual inclusions commonly seen in Tsavorite as well as some very unusual ones. Operating at the source, as we do, we see a great deal of Tsavorite rough, and are in a good position to photograph these.
Figure 1 "Snakeskin" Inclusion : To start off we wanted to showcase one of the most unusual inclusions we have observed in a Tsavorite. The "moss-like" or "net-like" inclusions seen above has only been observed in one crystal we have ever seen. The crystal tested positive as a Grossular Garnet on all tests.
Figure 2 Fingerprint Inclusion : This is a classic healed fracture or "fingerprint" inclusion often seen in Tsavorite crystals. These fascinating inclusions form during the process of the healing od a crack or fissure in a crystal. A fissure develops during the growth of the crystal and subsequent healing begins. Growth solutions flow into the fracture and the inner walls of the crack are partially dissolved, beginning the healing process. Then, dissolved nutrients are re-deposited on the inner walls of the crack as the healing proceeds. Eventually the fluid-filled cavities become more angular in shape, turning into fluid-filled negative crystals arranged in a fingerprint pattern.
Figure 3 Included Crystal Cloud and Needle Inclusions : Most Tsavorites will contain some of these inclusions. They are probably the most common inclusion in Grossular Garnet. Mostly formed from rutile or actinolite, needle inclusions are actually a different mineral growing within the Tsavorite. Conversely, included crystals like the cloud observed in the above image are generally garnets of various forms or trapped gases which have formed crystal faces due to slow cooling.
Figure 4 Nailhead spicules in Tsavorite. Nail-head spicules are inclusions that have traditionally been associated with synthetic emerald formed using the hydrothermal method. They are caused chiefly by rapid growth conditions and disturbances during crystallization of their host, such as that found during the synthesization process. However, nailhead spicules can occur naturally too in some gems. In this Tsavorite, their formation would likely have been due to a period of accelerated growth conditions according to Choudhary et al.
Figure 5 Aggregate Inclusion : Some Tsavorites can contain opaque black crystalline aggregates, some with unusual shapes like the one photographed above which has formed in a spiral. These aggregates are usually formed from Graphite..
Figure 6 Classic feather inclusion in a Tsavorite crystal. As Grossular Garnet forms under intense pressure, many crystals display evidence of stress fractures and feathers to varying degrees.
Figure 7 Rounded Aggregate Inclusion - Another example of an aggregate crystal in Tsavorite. High relief and rounded as aggregates tend to be.
Figure 8 Parallel Growth Tubes - Classic parallel growth tubes in Tsavorite. These usually align to the "C-Axis" in Tsavorite.
I hope the pictorial display we have provided here does justice in representing the wonderful "inner world" of Tsavorite. However, we intend to keep updating this page as we catalogue and observe new or different inclusions in coming years.
Copyright Lapigems 2016