Wednesday, November 16, 2016

Paraiba Tourmaline: The Neon Gems from Amazonia

Tourmaline gemstones and Paraiba are now commercially accepted as synonymous with each other. Considered as an electrifying item for jewellery and fashion, tourmalines bearing this characteristic shade owe their origin to north-eastern parts of Brazil. Much later, the sizzling varieties in effervescent green-blue were mined from Mozambique and Nigeria. If you are planning to buy a Paraiba tourmaline, there are chances that you might get confused between the ones coming from Brazil and those mined from Africa.


How are they different? Does it really count if they are from different sources? How to tell the difference between the two?

In terms of physical differentiation, it is very hard to find the variation between the Paraiba tourmalines from Africa and Brazil. Even under the microscope, they are hard to be differentiated.

So, how to differentiate? The only way gem labs can find the difference is by using quantitative chemical testing. Origin-wise, gem collectors rank Brazilian tourmalines higher than the ones mined from Africa. The African tourmalines have a reputation similar to what Burmese rubies enjoy in the gem lines.

History of Paraiba:

One of the recently discovered naturally-occurring gemstones, Paraiba tourmalines have a history dating back to 1980s, when Heitor Dimas Barbosa and his assistants dug out pegmatite deposits in the hilly areas of Paraiba in Brazil.

Why Paraiba gemstones are so popular?

The shady electrifying blue shade in the Paraiba tourmalines matches the beauty of blue sapphires. The blue colour appears due to the presence of copper oxides and hydroxides. Brazilian stones are darker in colour compared to their African counterparts by virtue of higher copper ions in the crystal structure.

Paraiba tourmalines exhibit a variety of colours ranging from sky blue to aquamarine to psychedelic blue. Highest variation in colour shades is observed in Mozambique Paraiba tourmalines.

World’s most famous Paraiba:

The Guinness World Records rank stunning Ethereal Carolna Divine Paraiba as the world’s largest, flawlessly cut naturally occurring Paraiba tourmaline in the world.  It weighs 191.87 carats and is enlisted in the same bracket as Logan Sapphire, Hope Diamond, The Golden Jubilee and Alan Caplan Ruby.

The Ethereal Carolina Divine Paraiba is an oval shaped tourmaline featuring Brilliant Cut, and is four times heavier than the second largest tourmaline ever mined. The stone now graces as a part in the necklace called Paraiba Star of Ocean. It entered the ranks in 2009 when the stone featured in the necklace designed by Canadian jewellery house- Kaufmann de Suisse.


This tourmaline exhibits a radiating neon blue-green colour very distinct from the traditionally mined stones. It is best described as the blue of the tropical ocean. Even the necklace it is fit into has been inspired from the aqua flora and fauna. A compliment to the marine animals like turtles, shells crabs, star fish, rays and sea horses, Paraiba tourmaline is flanked by the likes of canary yellow diamonds, blue, orange sapphires, ruby, garnet, emeralds, blue topaz gemstones and Tsavorite. The 191.87 carat Carolina tourmaline easily exceeds the size of all other gemstones.

Tuesday, November 15, 2016

Roman Love: Sizzling Garnet Varieties

Garnet bracelets are one of the world’s oldest recognised forms of gemstone jewellery. The Romans were known to adorn the rings and crowns adorned with garnets gemstones of different sizes.  They continue to be as impressive as they used to be in the 15th century. 

Garnets look like Pomegranate grains!

Yes, they do resemble the fruity grains. And that is why they are named from Latin word “Garanatus” that translates to “like seeds of pomegranate”. Small garnets are brighter in shade than the bigger ones. If you have difficulty analysing the authenticity of the garnet, get it tested under a refractometer. There are many varieties of garnets. Some of the popular varieties are:

o  Pyrope
o  Almandine
o  Grossular hessonite/ tsavorite
o  Uvarovite
o  Andradite
o  Rhodolite
o  Spessartine

Here are some less common, but very precious garnets available in the market sparingly.

o  Goldmanite
o  Morimotoite
o  Katoite
o  Hibschite
o  Kimzeyite
o  Schorlomite
o  Majorite
o  Calderite
o  Hydro-grossular
o  Knorringite
o  Kimberlites

World of synthetic garnets:


Garnet is one of the easily synthesised gemstones in laboratories.  Apart from silica, calcium and magnesium, garnets crystals can be impregnated with ions of Germanium, Gallium, Aluminium, Vanadium and Iron.

Very similar to zirconium, garnets too have their own series of synthetic gemstone members. Yttrium aluminium garnet- YAG, is one of the most popular and commercially accepted garnets to have made it big in the market. Other significantly popular synthetic garnets are Yttrium iron garnet- YIG, and Gadolinium gallium garnet- GGG. All synthetic garnet beads are coated with a film of magnetic substrate to replicate the magneto-optical properties as seen in the real gems.

So, how to identify a real garnet?

Physical testing for hardness, colour, magnetic properties and abrasive nature are popular methods used to separate original garnets from the synthetic ones.

Colours of garnet:

Garnets used in modern day jewellery exhibit myriad colours like red, orange, yellow, green, purple, brown, blue, black, pink and burgundy. Some garnets are pale and colourless as well which can be coloured after heat treatment.

Darker the colour of the garnet, older is the age of the gemstone. Depending on the diffusion, garnets can have shallow colouring as well as core colouring.

Discovered in 1990s, there is a special family of garnet called Blue pyrope–spessartine garnets. They exhibit multiple colour hues when observed from different angles. The colour changes from shades of green to purple, depending on the diurnal temperature and natural slight intensity.

Hardness:

Garnets is one of the hardest naturally available material on the planet. The synthetic garnets have hardness measured in Mohs scale. They could be anywhere between 6.5 and 7.8.

Magnetic Properties:

Easily the most authentic method to detect original garnets, magnetic susceptibility to neodymium magnet is a common feature among end members of the series.

But hey! Like all gemstones, garnets too can be faked and forged with impressive adulation. That is why there are certain restrictive trade regulations to keep only original garnets in the market. Find and assess gemstone certification that is tagged on every garnet.