Fluoralforsite, ideally Ba5(PO4)3F, (space group P63/m (#176), Z = 2, a = 10.0031(2) Å, c= 7.5382(2) Å and V = 653.23(3) Å3), is a new mineral species of the apatite group – a Ba-analogue of fluorapatite and a F-analogue of alforsite. It was discovered in rankinite paralava filling cracks in pyrometamorphic gehlenite hornfels near the tributary of wadi Zohar and Gurim Anticline, Hatrurim Basin, Negev Desert, Israel. Fluoralforsite occurs in small intergranular spaces between large gehlenite and garnet crystals and in enclaves inside large rankinite crystals with other Ba minerals such as walstromite, zadovite, bennesherite, gurimite, mazorite, barioferrite and baryte. It forms tiny transparent, colourless crystals up to 50 μm with a white streak and a vitreous lustre. The cleavage was not observed. It exhibits a brittle tenacity and a conchoidal fracture. The estimated Mohs hardness is 4–4½, and its calculated density is 4.57 g/cm–3. Fluoralforsite is uniaxial (–) with refractive indices (589 nm) nω = 1.689(3) and nɛ = 1.687(3). The empirical crystal-chemical formula for the holotype calculated on the basis of 8 cations is: (Ba3.81Ca0.97Na0.07K0.05Sr0.05Fe0.05)Σ5(P5+2.32V5+0.29S6+0.22Si0.17)Σ3O12(F0.85Cl0.13)Σ0.98. The crystal structure was refined from single-crystal X-ray diffraction data with R1 = 0.0192. The structural investigation indicated an ordered arrangement of Ba/Ca at the M1 site within individual columns running along the c-axis, but a disordered distribution among adjacent columns throughout the structure, which enables the maintenance of the P63/m space group. Fluoralforsite was formed at the final stage of crystallisation as a result of a reaction between the primary mineral assemblages and residual melt.

氟镁石，理想情况为 Ba 5 (PO 4 ) 3 F，（空间群P 6 3 / m (#176)，Z = 2，a = 10.0031(2) Å，c = 7.5382(2) Å 和V = 653.23(3) ) Å 3 ) 是磷灰石族的一种新矿物——氟磷灰石的 Ba 类似物和磷灰石的 F 类似物。它是在以色列内盖夫沙漠哈特鲁里姆盆地靠近佐哈干河和古里姆背斜支流的火变质钙黄长岩角岩充填裂缝的兰金长岩帕拉熔岩中发现的。氟铁镁石产于大型钙铝榴石和石榴石晶体之间的小粒间空间中，以及大型朗锰矿晶体内的包体中，并与其他 Ba 矿物（如硅锰矿、钾辉石、斜锰矿、硅锰矿、菱镁矿、重铁矿和重晶石）一起存在。它形成微小的透明无色晶体，最大可达 50 μm，具有白色条纹和玻璃光泽。没有观察到裂解。它表现出脆性韧性和贝壳状断裂。估计莫氏硬度为 4–4½，计算密度为 4.57 g/cm –3。氟镁石是单轴 (–) 的，折射率 (589 nm) n ω = 1.689(3) 和n ɛ = 1.687(3)。基于 8 种阳离子计算的正模经验晶体化学式为： (Ba 3.81 Ca 0.97 Na 0.07 K 0.05 Sr 0.05 Fe 0.05 ) Σ5 (P 5+ 2.32 V 5+ 0.29 S 6+ 0.22 Si 0.17 ) Σ3 O 12 (F 0.85 Cl 0.13 ) Σ0.98。根据单晶X射线衍射数据精修晶体结构，R 1 = 0.0192。结构研究表明，Ba/Ca 在沿c轴延伸的各个柱内的M 1 位置处有序排列，但在整个结构中相邻柱之间分布无序，这使得能够维持P 6 3 / m空间群。氟镁石是在结晶的最后阶段形成的，是原生矿物组合和残余熔体之间反应的结果。