Describe the dimensions of the jewellery you imagine in centimetres or millimetres. This will help us calculate the approximate weight of gold needed for its manufacture.
In the table, we have presented the inner diameter of each ring size and the corresponding European size (the size number corresponds to the inner circumference of the ring). For us, the only accurate method to determine the correct size is the use of jewellery measurements. All other methods we have tried result in minimal to significant deviations.
If you have a ring that fits, measure its inner diameter with a caliper.
*For orders we have already taken, we can provide and send jeweller’s measurements for you to take an accurate measurement.
If you have any questions, feel free to contact us for assistance.
| Diameter (mm) | EU |
|---|---|
| 14.3 | 45 |
| 14.7 | 46 |
| 15.0 | 47 |
| 15.3 | 48 |
| 15.6 | 48 |
| 16.0 | 50 |
| 16.3 | 51 |
| 16.6 | 52 |
| 17 | 53 |
| 17.2 | 54 |
| 17.5 | 55 |
| 17.8 | 56 |
| 18.1 | 57 |
| 18.4 | 58 |
| 18.8 | 59 |
| 19.1 | 60 |
| 19.4 | 61 |
| 19.7 | 62 |
| 20 | 63 |
| 20.4 | 64 |
| 20.7 | 65 |
| 21 | 66 |
| 21.3 | 67 |
| 21.7 | 68 |
| 22 | 69 |
Choosing a bracelet length is important, as most bracelets are difficult to shorten and lengthen. Below, we have outlined the recommended steps to help you determine the right length for your wrist.
If you have a bracelet that fits perfectly, measure its length including the clasp.
* Note that there may be a slight difference between your left and right wrist.
The choice of necklace length may depend on the characteristics of your body and the features of the jewellery. As a guide, we have graphically depicted the standard lengths of chains to help you visualize your options.
Paraiba tourmalines are some of the most expensive and rare tourmalines found in jewelry. Originally mined in Brazil in the state of Paraíba, the most expensive specimens are neon blue in colour due to their copper content. It is the copper content that is so important to their value. Their price can reach a staggering $30,000 per carat.
Subsequently, deposits have also been discovered in Africa and Afghanistan with similar characteristics and colours. Although these stones are not from Brazil they are also often referred to as Paraiba tourmalines in the jewellery trade.
Because of their extreme rarity, the only way to be sure that the stones offered are Paraiba is by testing in an established laboratory.
Before the 1980s, no one had even seen a tourmaline with a bright turquoise color. That changed thanks to Heitor Dimas Barbosa, a gem hunter from Brazil. In 1982, Barbosa began exploiting the Mina da Batalha located on a steep hillside near San José de Batalha in the state of Paraíba, Brazil. It took them about 6 years to find a specimen suitable for faceting. Between 1990 and 1991 the maximum production from the mine took place.
Similar specimens of copper-bearing tourmalines were found in the 1990s at two other mines in a neighboring state, the Mulungu and Baixa Dos Quintos mines.
Most Brazilian Paraiba tourmalines weigh less than 1 carat, with only few specimens weighing in the range of 10-20 carats on record. They are extremely expensive and are owned by private collectors. The Brazilian mines are now almost completely exhausted and mainly small specimens are found.
In 2001, copper-bearing tourmalines from Nigeria and Mozambique appeared on the market. Their colours range from violet blue to bluish green to green.
In fact, there are not many differences between Brazilian and African paraiba tourmalines. They are indistinguishable to the naked eye and even difficult to report differences under a microscope. According to the Gemological Institute of America, they cannot be distinguished by standard gemological tests, only by chemical testing in a laboratory.
10.14 carat bright green Paraiba tourmaline necklace from Mozambique and diamonds by Louis Vuitton/Photo: Pinterest
It is customary to refer to African specimens as "Paraiba-like", but due to the near depletion of Brazilian mine deposits and the growing interest in stones of other origins, it seems that this addition is being phased out.
Yet original Paraiba tourmalines sourced from Brazil always trade at a much higher price.
No matter where the stones were mined, they are usually heated to give them the much desired bright "neon" color. According to the GIA, about 80% of Brazilian tourmalines have been heated to obtain the "Paraiba" color.
In this section we will list the factors that determine the price of copper-containing tourmalines.
When Paraiba tourmalines are being evaluated, color and luster are of paramount importance. The gemstones must have a good quality cut and be lustrous to receive maximum value. They are cut primarily in elongated shapes, such as oval and pear.
The better the quality of the cut of the specimen, the higher its price.
Treating is a commonly used and accepted practice. It raises the price of copper-bearing tourmalines as highly desirable colors such as "neon blue" are achieved.
Filling cracks and impregnating the stones has a negative effect on the value and drastically reduces the price.
When the stone is accompanied by a certificate of origin from an established laboratory, Brazilian copper-bearing tourmalines are significantly more expensive than those mined in Africa due to their extreme rarity.
If the tourmaline meets the copper content standards of established gemological laboratories, its price skyrockets compared to non-copper containing tourmalines.
Beautiful blue and green tourmalines that do not contain copper are common in the market. In these the colouring is due to other elements such as iron, chromium and vanadium. They are considerably more affordable and we recommend you go for this type if you want to own a piece of jewellery with blue and/or green tourmaline. However, if the colour rather than the type of natural stone is the main factor then you could look at other options - for example natural Apatite.
Paraiba tourmalines from Brazil are some of the most expensive and rare tourmalines found in jewellery. The most desirable specimens are turquoise blue in colour, which they attribute to their copper content. Subsequently, deposits have also been found in Africa and Afghanistan and usually traders also refer to these tourmalines as "Paraiba" despite the fact that their origin is not from the eponymous state in Brazil.
Because of their extreme rarity, the only way to be sure that the stones on offer are Paraiba is by testing them in an established laboratory. There are also affordable blue and green tourmalines on the market, which owe their colour to their iron, chromium and vanadium content instead of copper.
Efir offers both jewellery with tourmalines from its own collections and making gold jewellery with tourmalines and other gemstones according to client's design requirements and budget. We work only with natural gemstones and precious metals. Our Expert Gemologist will take care of finding the perfect matching gemstone.
You can contact us via contact form, Facebook, Instagram or our phone number (+359) 898 241940.
