A gem-quality purplish-red tourmaline sample of alleged liddicoatitic composition from the Anjanabonoina pegmatite, Madagascar, has been fully characterised using a multi-analytical approach to define its crystal-chemical identity. Single-crystal X-ray diffraction, chemical and spectroscopic analysis resulted in the formula: X(Na0.41□0.35Ca0.24)Σ1.00Y(Al1.81Li1.00Fe3+0.04Mn3+0.02Mn2+0.12Ti0.004)Σ3.00ZAl6 [T(Si5.60B0.40)Σ6.00O18] (BO3)3 (OH)3 W[(OH)0.50F0.13O0.37]Σ1.00 which corresponds to the tourmaline species elbaite having the typical space group R3m and relatively small unit-cell dimensions, a = 15.7935(4) Å, c = 7.0860(2) Å and V = 7.0860(2) Å3.

Optical absorption spectroscopy showed that the purplish-red colour is caused by minor amounts of Mn3+ (Mn2O3 = 0.20 wt.%). Thermal treatment in air up to 750°C strongly intensified the colour of the sample due to the oxidation of all Mn2+ to Mn3+ (Mn2O3 up to 1.21 wt.%). Based on infrared and Raman data, a crystal-chemical model regarding the electrostatic interaction between the X cation and W anion, and involving the Y cations as well, is proposed to explain the absence or rarity of the mineral species ‘liddicoatite’.

来自马达加斯加Anjanabonoina伟晶岩的宝石品质紫红色电气石样品，据称是含锂辉石成分的，已使用多种分析方法进行了充分表征，以定义其晶体化学特征。单晶X射线衍射，化学和光谱分析得到，式中：X（钠0.41 □ 0.35的Ca 0.24）Σ1.00 Ý（铝1.81栗1.00的Fe 3+ 0.04的Mn 3+ 0.02的Mn 2+ 0.12的Ti 0.004）Σ3.00 ž的Al 6 [ Ť（硅5.60乙0.40）Σ6.00 Ô 18 ]（BO 3）3（OH）3 w ^ [（OH）0.50 ˚F 0.13 ö 0.37 ] Σ1.00其对应于电气石物种elbaite具有典型空间群[R 3米和相对小单位晶胞尺寸，一个= 15.7935（4），C ^ = 7.0860（2）埃，V = 7.0860（2）埃3。

光学吸收光谱表明，紫红色是由少量的Mn 3+（Mn 2 O 3＝ 0.20wt。％）引起的。由于所有Mn 2+都氧化成Mn 3+（Mn 2 O 3高达1.21 wt。％），因此在高达750°C的空气中进行热处理会大大增强样品的颜色。基于红外和拉曼数据，提出了有关X阳离子和W阴离子之间的静电相互作用以及Y阳离子也涉及的静电相互作用的晶体化学模型，以解释“ liddicoatite”矿物物种的缺乏或稀有性。