In the past several years, Mozambique has emerged as one of the world's most important sources of ruby, and unheated stones from this country are in particularly strong demand. Nevertheless, it is common for these rubies to undergo low-temperature heating (~1,000°C or below) to slightly improve their colour. The treated stones may show very subtle or no alteration of internal features (e.g. mineral inclusions, 'fingerprints', needles, 'silk', etc.). However, 'iron-stained' surface-reaching fractures in the rubies commonly display a noticeably more intense colour after heating. Raman and FTIR spectroscopy were used to document a transition from goethite to hematite within stained fractures in samples heated to 500°C and 600°C. The identification of hematite within such fractures provides key evidence for the low-temperature heat treatment of Mozambique ruby.

Although taaffeite from Myanmar was reported over 30 years ago, few gemmological studies have been published on this material. Five specimens of very pale purplish pink and heavily included taaffeite from the Mogok area were characterized for this report. Chemical analysis revealed 75.2-76.4 wt.% Al 2 O 3 and 18.2-19.1 wt.% MgO, with trace amounts of Fe, Zn, Ga, Mn and other elements. Compared to similarly coloured taaffeite from Sri Lanka and Africa, these Burmese samples showed no significant differences except for lower Fe content.

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