**1.6.1. Svabite**

Svabite is rare accessory mineral in calc-silicate skarns and arsenate analogue of fluorapatite [15] with the composition given by the formula Ca10(AsO4)6F2 (calcium fluorarsenate, CAAP). The mineral was named in 1981 by SJÖGREN [159] according to the Swedish chemist ANTON VON SWAB (1703–1768), who distilled zinc from calamine (smithsonite, ZnCO3 [160]) [161]. Svabite has the same crystal habit as apatite, with rough hexagonal prisms, some of which show rounded pyramidal termination [162]. The structure of mineral svabite is shown in **Fig. 23**.

**Fig. 23.** The structure (perspective view along the *c*-axis) and examples of crystal habits of svabite.

**Fig. 24.** Known localities for the mineral svabite.

It is brittle mineral that can be white, gray, gray-green, or colorless and transparent. The mineral is considered to be the intermediate between the apatite and the pyromorphite series. Svabite has the average density of 3.7 g·cm−3, and the hardness on the Mohs scale ranges from 4 to 5. It is hexagonal mineral belonging to the space group P63/M, *a* = 9.75 Å and *c* = 6.92 Å, *a*:*c* = 1:0.71, *V* = 569.7 Å3 , and *Z* = 2. The mineral occurs in the localities introduced in **Fig. 25**.
