This natural tourmaline from Pakistan is a semi-precious stone prized for its aesthetic qualities and beauty. It has an oval shape and brown colour, measures 5.90x5.60 mm, and weighs 0.95 carats, indicating an ideal size and weight for mounting in a variety of jewellery. The clarity of this stone is exceptional, with no visible inclusions, adding to its value and appeal. The fact that it is untreated suggests that it retains its natural beauty and internal structure without artificial alterations. This tourmaline is ideal for those looking for an authentic, unaltered semi-precious stone, perfect for adding an accent of natural elegance to any piece of jewellery.
Tourmaline (or tourmaline) is a semi-precious crystal with a variable chemical structure and a complex silicate of aluminium and boron. Atoms of sodium, calcium, magnesium, iron, lithium, etc. can be substituted for aluminium atoms in various proportions, resulting in variations in the physical properties of the crystal. Tourmaline is one of the minerals with a trigonal crystallisation system. The chemical formula shows that hydroxyl ions (-OH) and fluorine ions (-F) can combine in different mixing ratios with metals; this mixture determines the colour and hardness of the mineral (between 7 and 7.5). Tourmaline colours are very varied, ranging from blue, green, red, pink, brown and black. Sometimes one crystal can have more than one colour; in cross-section, some crystals appear as an agate with concentric circular lines of different colors. Tourmalines often show the phenomenon of pleochroism, i.e., changing colour depending on the direction of observation. The most common pleochroism is from blue to black. Another property of tourmaline crystals is piezoelectricity, which manifests itself in the electrical polarisation of the crystal as a result of a mechanical action (pressure or torsion) applied to a certain axis of the crystal. Most tourmaline varieties also exhibit pyroelectricity, i.e., the occurrence of electrical polarisation when the crystal is heated or cooled. Tourmaline is the first material in which these two properties have been observed. The term tourmaline came into Romanian from other European languages (German Turmalin, French tourmaline). However, the origin is the Sinhalese (the majority language spoken in Sri Lanka) word turamali, meaning'stone that attracts ash', which reflects tourmaline's pyroelectric properties.
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