Jammu and Kashmir Bridal Jewellery.
By Aamir Mannan.
By Aamir Mannan.
5..DOUBLE REFRACTION AND DISPERSION
As would appear in a singly refractive stone such as diamond, each edge appears as a double line (see figure 3.1). a word of warning, however, should be uttered here; according to their crystal structure, all doubly refracting stones have either one or two direction in which only single refraction obtains. those gemstones belonging to the tetragonal, trigonal or hexagonal system
of crystals have only such direction; one 'optic axis' as it called. these minerals, which are grouped together optically us 'uniaxal', include zircon, corundum (ruby and sapphire), beryl (emerald and aquamarine), tourmaline, and quartz (amethyst and citrine). the minerals crystallising in either the orthorhombic, monoclinic or triclinic systems have two optic axes, and are called 'biaxial'. these include peridot, chrysoberal (alexandrite), topaz, and spodumene (kunzite) among the coommoner gemstones.
.jpg)
1 comments:
I just came back from Pearls jewellery London last week. It is such a delight to have my pieces on display in London's famous Burlington Arcade. My new collections were very well received alongside my more familiar signature pieces.
Post a Comment