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TOURMALINE -RICH DARK BI COLOUR 2.25 CTS [S5656]

SKU
Dimensioni (mm)
9.000 x 6.000 x 4.000mm
Peso (cts)
Certified Gemstones
NO
Colori

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Member of International Coloured stone asociation commited to full disclouser of  stone with money back guarantee

SEDAGEMS

TOURMALINE BIRTHSTONE FOR OCTOBER.

This is a rich bi coloured Tourmaline. 

 

NATURAL UNHEATED

MINED IN BRAZIL 

MOHS SCALE 7-7.5

WEIGHT  2.25  CTS

SIZE   9 x 6 x 4 MM


Except for gem materail most other stones have some inclusions in them.To date heat treatment dosent enhance the stones so they are natural

Often, Nature conjures up tourmaline crystals from which gemstones with a particularly subtle multi-colouredness can be cut. You may well ask how that is possible. Tourmalines are mixed crystals of aluminium boron silicate with a complex and changing composition. It's a rather complex mineral group. Even minor changes in composition cause completely different colours. And that is how, on one and the same crystal, although it has grown quite naturally, completely different colours can occur, mostly in elongated columns one above the other, as if Nature had piled coloured rings one on top of the other. The crystals themselves can be as slim as a knitting-needle or as thick as a man's thigh. Some display coloration in which the shades vary only slightly, whilst others have starkly contrasting colours or zones of colour. Since tourmaline crystals have often grown in close proximity to one another, their cross-sections can also contain triangles which are closely joined together and gathered around a nucleus.

 

Stones with two or more different, well represented colours are particularly desirable. Depending on their shape and colour, these are known in the trade as bicoloured and multicoloured tourmalines respectively. Some of them also have rather interesting names: if, for example, the crystal is almost colourless and just black at both ends, it is referred to fondly as a 'Mohrenkopf', (a kind of cake popular in Germany). If it was red at one end it used to be called a 'Turk's head tourmaline'. Bicoloured tourmalines with a red centre which changes to green towards the edges are still referred to as 'watermelons'. If the colour zones of the crystal lie on top of one another, the Brazilians call it a 'papageios' or 'rainbow tourmaline'.

The main deposits of tourmalines are in Brazil and Africa. But Nature has also made Man a gift of this beautiful gemstone, always good for a surprise on account of its great diversity of colour, at other deposits, for example in Sri Lanka and Madagascar.

Pure individuality

Tourmalines are popular not only in jewellery but also as therapeutic stones. Thanks to their good energetic conductivity and their wealth of minerals, they are said to have an invigorating and fortifying effect. They are uncomplicated to work with and have excellent wearing qualities thanks to their good hardness. Beautiful multi-coloured tourmalines are particularly well suited to jewellery of an individual design, for each of these stones is different. More than that, indeed: practically each of the places where this gemstone is found - and it occurs all over the world - has its own colour variant. That does make life somewhat difficult for the cutter if he has to look for several stones of the same colour; in fact even two stones cut from the same raw crystal often differ in colour. But then that is the charm of the tourmaline, and especially that of the multi-coloured tourm

 

 

 

 

 

 

 Tourmaline is a crystal silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline gem stones come in a wide variety of colors.Tourmaline has a variety of colors. Usually, iron-rich tourmalines are black to bluish-black to deep brown, while magnesium-rich varieties are brown to yellow, and lithium-rich tourmalines are almost any color: blue, green, red, yellow, pink etc. Rarely, it is colorless. Bi-colored and multicolored crystals are common, reflecting variations of fluid chemistry during crystallisation. Crystals may be green at one end and pink at the other, or green on the outside and pink inside: this type is called watermelon tourmaline. Some forms of tourmaline are dichroic, in that they change color when viewed from different directions.

Type 1 Gemstones
The following gemstones are typically inclusion free, even minor inclusions detract from their value.
Diamond, Amethyst, Beryls(Aquamarine,Morganite), Citrine, Smoky Quartz, topaz, Chrysoberyl, Kunzite, Tanzanite, green Tourmaline, and Blue Zircon
IF Internally flawless under extreme magnification (Very rare)
F Flawless
VVS Minute inclusions under 10x; invisible to the unaided eye
VS Minor inclusions under 10x; usually invisible to the unaided eye
SI1 Noticeable inclusions under 10x; usually visible to the unaided eye
SI2 Noticeable inclusions under 10x; usually quite visible to the unaided eye
I1 prominent- moderate affect on appearance or durability
I2 prominent - severe affect on appearance or durability
I3 prominent- severe affect on beauty, transparency or durability
Type 2 Gemstones
Gemstones that normally have small inclusions that do not detract from value.
Alexandrite, Andalusite, Iolite, Peridot, Rhodolite, Ruby, Sapphire, Spinel, Tourmaline, Garnet, Amethyst, Red Zircon, Tsavorite; Blue, Orange, Purple, Fluorite.Yellow and Parti-colored Tourmaline
F Flawless
VVS Minor inclusions under 10x; usually invisible to the unaided eye
VS Noticeable inclusions under 10x; often invisible to the unaided eye
SI1 Obvious inclusions under 10x; visible to the unaided eye
SI2 Obvious inclusions under 10x; very apparent to the unaided eye
I1 prominent - moderate affect on appearance or durability
I2 prominent - severe affect on appearance or durability
I3 prominent - severe affect on beauty, transparency or durability

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sedagems
Hi Welcome to the Sedagems store, Run by Paul Sedawie and specializing in Australian sapphires and gems stones he has collected on his many buying trips world wide. All stock has a money back guarantee as your continued business is our business.
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  • royrock
    royrock
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    Beautiful agate piece , and as always fast efficient service from Sedagems

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Tipo di elenco : Standard
Codice prodotto : 229246
Inizia : 21st November 2024 05:00 pm PST
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