**1. Introduction**

Kammererite mineral, which is rarely found in the world, is found in chromite deposits as reddish pink or purple-violet [1] colors as transparent or semitransparent. Its hardness is around 2.5, and its specific weight is 2.645 g/cm3 [2, 3].

Kammererite mineral is one of the clinochlorine members of chlorite group in phyllosilicates. Clinochlore, which is one of the most common members of the chlorite group minerals [4], can be divided into three subvarieties according to body colors and implicational abundance of the main cations [5–11]. These are blackishgreen or bluish-green colored clinochlore (ferroan clinochlore) [12], yellowishgreen or green colored clinochlore (magnesian clinochlore) [13, 14], and magenta colored clinochlore (chromian clinochlore) [5, 11, 15–17]. In fact, it is well-known that the name clinochlore derived from "clino," which refers to the inclined optical axes and the Greek "chloros," for "green," its most typical color [4, 11, 18, 19].

Chromian clinochlore (kammererite) represented by the formula [Mg5(Al,Cr,Fe)2 Si3O10(OH)8] [8, 9] is a hydrous silicate with a monoclinic IIb-2 polytype, with symmetry C2 = m, and is extremely rare and of high interest for mineral collectors [20].

Worldwide occurrences of chromian clinochlore (kammererite) in addition to Turkey are as follows: Australia (Coobina chromite mine, Sylvania Station, Meekatharra Shire, Western Australia), Austria (Gulsen, Sommergraben, Lobminggraben, Leoben, Styria), Ethiopia (Tumut River, Sosua Region, Benishangul-Gumaz Province), Finland (Elijarvi Cr Mine, Kemi, Lapland Region), Greece (Nea Roda, Chalkidiki Prefecture Macedonia), Italy (Locana, Orco Valley, Torino Province, Piedmont), Japan (Akaishi Mine, Ehime Prefecture, Shikoku Island), Russia (Poldnevaya village, Sverdlovsk Oblast, Middle Urals), and the United States, (Dunsmuir, Siskiyou Co., California; Cecil Co., Maryland; Green Mountain Mine, Day Book, Yancey Co., NC; Jackson Co., Oregion; Woods Chrome Mine, Texas, Little Britain Township, Lancaster Co., PA) [20].

## **2. Material and methods**

Samples were taken from the study area in order to determine the distribution, the paragenetic relationships, and the mineralogical, geochemical, and gemological characteristics of kammererite. It has been engraved on 1/25000 map. Thin sections were prepared from kammererite and side rock samples taken from the field in thin-section laboratory of Kırşehir Ahi Evran University Geological Engineering Department. Mineralogical determinations (mineral paragenesis) were carried out by examining these samples under a polarizing microscope in Kırşehir Ahi Evran University Geological Engineering Mineralogy-Petrography Laboratory.

In addition, gem-cutting techniques were applied to the kammererite samples taken from the field by using diamond coating saw, sinter diamond abrasive discs and polishing machine, and the usability of kammererites as a gemstone was present.

Kammererite samples taken from the study area applied gem-cutting techniques in the Gemology Laboratory of Mersin University, School of Jewelry Technology and Design.

First, slices of coarse material were taken on the large cutting machine, and different shapes were marked. Edge trimming was done on the small cutting machine, and curves were made on the cabochon machine. Finally, abrasive and polishing processes were carried out to form cabochon stones. Because kammererite are fine grains and fine veins, it cannot be processed alone. For this reason, it was worked together with the side rock. The obtained gems can be used in jewelry as necklaces, rings, earrings, bracelets, brooches, and functional goods such as keychains.

Treatment studies of kammererite samples were carried out in the natural stone analysis laboratory of Kaman Vocational School of Kırşehir Ahi Evran University. First, the samples were kept in the oven at 75°C for one day to allow them to completely exhale. Then, the hot samples were kept in the mixture of epoxy and hardener for 1 day. As a result, the epoxy penetrated the capillary cavities of the samples, and the samples had a solid structure. Epoxy-treated specimens were processed using cabochon and simple step cutting methods.

### **3. Geology**

The study area is located in the Middle Pontid Tectonic Belt [21], south of Tokat province.

Tokat metamorphites [22], which represent the oldest unit in the study area and contain schist, phyllite, marble, and metabasites, are Upper Paleozoic-Triassic and

**67**

alluviums.

**Figure 1.**

*Geological map of the study area [23].*

**4. Findings**

(**Figure 4**).

semitransparent.

**4.1 Field studies**

rocks reaching up to 40 cm (**Figure 3**).

*Mineralogical-Petrographical Investigation and Usability as the Gemstone…*

are overlain by Mesozoic basic and ultrabasic rocks which are part of the ophiolitic series (**Figure 1**). These basic and ultrabasic rocks are overlain by Upper Cretaceous volcanic and sedimentary units. The youngest units in the study area are Quaternary

Kammererite formations in the region including Beşören and Saltık Villages within the borders of Tokat province in northern Anatolia are in purple-violet and reddish pink color and are in the form of nodules (**Figure 2a, b, d, e**) or veins (**Figure 2c, f**) within the chromium levels within the Mesozoic basic-ultrabasic

Thin sections prepared in order to determine the mineral associations and textural relationships of the rock samples taken from the study area were examined under a polarizing microscope. Chromium minerals are observed as black color in plane-polarized light and crossed polars because they are opaque minerals

Kammererite minerals has microcrystalline size. While the colorless, grayish, brownish, and pinkish pleochroism was observed in the plane-polarized light in the kammererite mineral (**Figure 4b, d, f, h**), the interference colors in black and white

It was observed in the surface investigations that kammererite minerals did not show a widespread distribution. Kammererite minerals in the study area have different shades of pink color and glassy brightness and are either transparent or

**4.2 Mineralogical-petrographical-gemological investigations**

gray tones were observed in the crossed polars (**Figure 4a, c, e, g**).

*DOI: http://dx.doi.org/10.5772/intechopen.92153*

*Mineralogical-Petrographical Investigation and Usability as the Gemstone… DOI: http://dx.doi.org/10.5772/intechopen.92153*

#### **Figure 1.** *Geological map of the study area [23].*

are overlain by Mesozoic basic and ultrabasic rocks which are part of the ophiolitic series (**Figure 1**). These basic and ultrabasic rocks are overlain by Upper Cretaceous volcanic and sedimentary units. The youngest units in the study area are Quaternary alluviums.
