Peruvian Black Jade

Gemstone Quality Standard

About Peruvian Black Jade

Peruvian black jade (also called Lemurian jade) is mined within the area of the capital Lima. It is a soft porous stone.

Because of its internal structure the polish never gets to the shine one is used to from other black stones like obsidian but rather stays a little more dull. We at Gemrock Peru, however, have developed a technique of dry polishing that provides the best possible polish on this stone.

Peruvian black jade comes many times with tiny pyrite sparkles or fine pyrite lines included, which is a good way to differentiate Black Jade from other black stones.

There is no geological information about black jade available. It must be related to marine sediments, as there are frequently crab fossils found in the black jade. 

Black Jade Quarry in Lima, Peru

Rarity

Peruvian Black Jade (also called: Lemurian Jade) can only be found in a “semi-abandoned” quarry, located in the southeastern city limit of the capital. Only two families of artisans quarry there and extract material for tiles and stone steps.

The quarry is approximately 100 by 100 meters in size. Even though all the rock there looks the same at first sight, there are only three small spots of approximately 10 by 10 meters in size where the black jade is dark black and stable. In more than 90 percent of the quarry, the material is soft, unstable, and dark greyish. Only the material of the three small spots can be used for stone carving. Jewlery-grade and Premium jewelry grade material, which contains Pyrite flecks and lines, makes up maybe 5 % of the material that is useful for stone carving. Therefore, jewelry-grade material is, in fact, an extremely rare material.

Color

Unsuitable material:

Dark-greyish material, sometimes with yellowish impurities, as well as dark black but unstable material.

Decor-grade material:

Uniformly black material. No Pyrite lines are present. Rarely a few tiny pyrite flecks are present.

Standard jewelry grade material:

Uniformly black material. Tiny pyrite flecks are present in low-concentration.

Top-quality jewelry-grade material:

Uniformly black material. Small pyrite flecks are present in high concentrations or/and pyrite lines are present.

Rare jade/quartz mix:

Extremely rare: one can find small veins of milky quartz accompanied by pyrite veins and highly concentrated pyrite flecks in black material.

Ethical and environmentally friendly mining

Black Jade is mined 100 % ethically and environmentally friendly by Gemrock staff by hand in an open quarry. No explosives are required. The only tools required are a hammer and water spray to check quality. The material is then paid by the kilo to the local artisan families who quarry here.

Polishable

Because of its porous structure, it is impossible to polish Black jade to glass finish. It always looks dull black when dried after the polishing process. At Gemrock we found a new method to polish the material to the best possible polish. 

Cutting Quality

Advantages:

Black Jade does not tend to break or chip. Experienced cutters therefore can obtain very sharp unchipped edges between the backside and bezel as well as between the bezel and dome.

Premium-cutting-quality is characterized by:

  • a polished backside
  • a sharp unchipped edge between the backside and the bezel
  • a very straight and even highly polished bezel
  • a sharp unchipped edge between the bezel and the dome
  • a well-shaped dome, not showing any deformation
  • best possible polish
personalized jewelry silver pendant on carved black jade crystal backplate

Pricing

Adequate pricing must take into account the cost factors to obtain top-quality cabochons:

  • Acquisition of top-grade Black Jade with strong color and high Pyrite concentration in the mine.
  • Selection of material and discarding more than 90 percent of the mined rough rock as unsuitable for jewelry.
  • A usual material loss is approximately 90 % of the selected material during cutting and shaping.

Jewelry Grade Material:

black, without pyrite flecks or lines, and no greyish impurities.

Cutting Quality:

  • Straight bezel (minor irregularities possible), 3 mm high
  • Perfect dome (3-5 mm high)
  • Edges between bezel and dome, as well as bezel and backside: sharp and crispy, minor chips on lower edge possible
  • Backside flat at 280 grit, unpolished

Pricing:

Recommended Retail Price (A): 0.39 USD per carat

Jewelry Top-Grade Material:

black with more or less evenly distributed pyrite flecks, and no greyish impurities

Cutting Quality:

  • Straight bezel, 3 mm high
  • Flat and perfect dome (3 mm high)
  • Edges between bezel and dome, as well as bezel and backside: sharp and crispy, minor chips on lower edge possible but very rare.
  • Backside flat, at 280 grit

Additional Quality (AA+): Backside polished

Pricing:

Recommended Retail Price (AA): 0.69 USD per carat

AA+: 0.79 USD/c

Premium Jewelry Grade Material:

black with a high concentration of pyrite flecks, big pyrite spots, or pyrite lines

Cutting Quality:

  • Only cut by our best master cutters
  • Straight bezel, 3 mm high
  • Flat and perfect dome (1-3 mm high)
  • The edges between the bezel and dome, as well as the bezel and backside, are sharp and crispy, with no chips on the lower edge.

Additional quality (AAA+): Backside polished

Pricing:

Recommended Retail Price (AAA): 1.00 USD per carat

AAA+: 1.09 USD per carat

Premium Jewelry Grade Material with quartz:

black with a high concentration of pyrite flecks, big pyrite spots, or pyrite lines and mixed with quartz

Cutting Quality:

  • Straight bezel, 3 mm high
  • Flat and perfect dome (1-3 mm high)
  • The edges between the bezel and dome, as well as the bezel and backside, are sharp and crispy, with no chips on the lower edge.

Additional Quality (AAA+): Backside polished

Pricing:

Recommended Retail Price (AAA): 1.50 USD per carat

AAA+: 1.59 USD/c

Peruvian Black Jade is rarely offered as cabochon on the internet. There is not enough data available to calculate average prices. Cabochons with Premim jewelry-grade material have been found to be sold at up to 1.5 USD per carat. 

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personalized jewelry silver pendant on carved black jade crystal backplate
Peruvian black jade also called lemurian jade
Engraved cabochon hand made from Peruvian Black Jade
Engraved cabochon hand made from Peruvian Black Jade
Engraved cabochon hand made from Peruvian Black Jade
Engraved cabochon hand made from Peruvian Black Jade
Peruvian black jade also called lemurian jade
Peruvian black jade also called lemurian jade
Engraved cabochon hand made from Peruvian Black Jade
Peruvian black jade also called lemurian jade
Peruvian black jade heart
Engraved cabochon hand made from Peruvian Black Jade
Peruvian black jade heart
Peruvian black jade heart

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