Indian Rakhi Gents Bracelet Jewellery Collection 25

Indian Rakhi Gents Bracelet Jewellery.
6.COLOUR, COLOUR FILTERS, AND THE DICHROSCOPE
By Aamir Mannan.

While ruby and supphire are the red and blue varieties of the mineral corundum, there are also white, yellow, pink and green supphires. emerald and aquamarine are the rich green and pale blue varieties of beryls, but there are also white, pink, and yellow beryls, and green beryl that do not rank as emeralds, tourmaline, quartz, zircon and topaz are further well-known examples of such polychrome minerals, and tourmaline in particular 

is well known for frequently appearing as parti-coloured crystals, the boundaries between the colours -(usually green and pink) being quite sharp either across the length of the crystal or concentrically in zones. the reason of such confusing behaviour can usually be explained by the fact that there are a limited number (eight to be precise) of elements that give rise to colour in minerals.