Gemstone Standards

What is a gemstone?

A very general and broad definition is:

A gemstone is any type of mineral, crystal, or rock that can be cut and polished and can be used in jewelry production.

Within the group of gemstones we can distinguish three subgroups:

1. Precious Gemstones: Generally only four gemstones in the world are classified as precious gemstones: emeralds, rubies, sapphires, and diamonds.

2. Semiprecious gemstones: Several gemstones are considered semiprecious: Amethyst, Aquamarine, Citrine, Garnet, Onyx, Opal, Peridot, Tanzanite, and Topaz.

3. Gemstones: Any other crystal, rock, or mineral that can be used for jewelry

However, the terms “precious stone” versus “semi-precious stone” are purely commercial terms, created as a marketing tool to sell precious stones. When amethysts were rare, they were considered precious, but as soon as huge reserves of amethysts were found in many parts of the world, this gemstone stopped being referred to as a precious stone.

There are many examples of semi-precious stones that demand a higher price than precious stones. For example, a Tsavorite green garnet is more valuable than a mid-quality sapphire.

Many semi-precious stones are also rarer than precious stones. For example, Red beryl, ammolite, benitoite, or gem silica are mined in fewer locations and produced in smaller quantities than any of the precious stones.

Transparency:

Another way to distinguish gemstones is transparency. Precious and semiprecious gemstones are always showing transparency.  Non-precious gemstones can be transparent, translucent, or opaque.

Facetted or cabochon

A third way to distinguish gemstones is the type of cut. Precious and semiprecious gemstones are almost always faceted, as the transparency of those stones allows for the light to pass and produce the incredible shine of such gemstones.

Other gemstones may show transparency or at least translucency and therefore may be faceted too. But most other gemstones, and especially the opaque ones are cut into cabochons, instead of being faceted.

Semiprecious gemstones of Peru

Peru offers you a huge variety of gemstones. However, our geology does not produce any of the four precious gemstones.

Peru offers you 4 types of semiprecious gemstones:

• Gem silica
• Pink Opal
• Andean, or blue opal
• Black Iris Opal

Gemstone standards – the problem

Precious and semiprecious gemstones are generally graded by color, cut, clarity, and carat weight. Grading criteria are well established and several institutions offer professional education on how to grade and determine the stones’ value.  

When it comes to non-precious gemstones, opaque gemstones, and gemstones used for cabochons, grading standards do not exist. Given the lack of objective verifiable standards and criteria, every seller allocates quality terms as he wishes.

One of the most common grading scams is to allocate terms like A-grade, AA-grade, or AAA-grade to a gemstone without providing any information what are the criteria for such kind of classifications. As a result, we can find very low-grade material (so low that we at Gemrock would not even consider using it for cheap decor carvings, even less for jewelry) being labeled as AAA-grade.

As a result of everyone allocating non-factual grades, there is also no standard for pricing which results in terribly overpriced junk material being offered aside from very high-quality material being sold at lower prices than the crappy material.

Such chaos makes it impossible for customers to appreciate cabochon quality and opens the doors to ripping off customers.

Gemrock Gemstone standards

Our Gemrock gemstone standards will help you avoid falling victim to quality grading scams. They will help you identify real jewelry-grade material from all Peruvian gemstones. They will help you to identify fair and adequate pricing for the gemstone quality.

if you combine our gemstone standards with our cutting standards for cabochons, you will be able to identify the top-quality cabochons and get the best for your money, while radically improving the quality of your jewelry and standing out of the crowd.

In order to create a gemstone standard for each of the Peruvian gemstones we are applying objective and factual criteria that can be used to classify material quality. Our criteria are:

• Rarity: how rare is the gemstone
• Clarity: only applied for transparent and translucent gemstones.
• Inclusions: only applied for transparent and translucent gemstones
• Color: subdivided in strength of color and uniformity of color. Can be applied to all gemstones.
• Contrast/definition: Applied to multicolor opaque gemstones that show patterns.
• Impurities: Applied to opaque gemstones
• Presence/absence of pores: Applied to opaque gemstones
• Polishable: This criterion does not refer to the craft of polishing. It refers to the physical composition of the stone that allows to polish the stone. In some gemstones, it is impossible or very difficult to polish them to glass-finish and they rather stay kind of satinated by nature.

Agate – Quality Standard

Angelite – Quality Standard

Apatite – Quality Standard

(Banded) Aragonite – Quality

Standard

Coati Aragonite – Quality Standard

Red Aragonite – Quality Standard

Tiger Aragonite – Quality Standard

Atacamite – Quality Standard

Azurite / Malachite –

Quality Standard

Azurite “Ocean Blue” –

Quality Standard

Black Jade – Quality Standard

Black Iris Opal – Quality Standard

Blue Andean Opal –

Quality Standard

Caramel Calcite – Quality Standard

Cherry Blossom Stone (Cinabrite) –

Quality Standard

Chocolate Calcite – Quality

Standard

Chrysocolla – Quality Standard

Green Jade – Quality Standard

Epidote Crystal – Quality Standard

Hematite with Mica – Quality Standard

Huanucite – Quality Standard

Jasper – Quality Standard

Landscape Jasper – Quality

Standard

Leopardite – Quality Standard

Manganocalite – Quality Standard

Morning Rose Granite –

Quality Standard

Pink Opal – Quality Standard

Canadian Pinolite – Quality Standard

Pyrite – Quality Standard

Quantum Cuatro – Quality

Standard

Quartz – Quality Standard

Red River Sunset Travertine –

Quality Standard

Rose Quartz – Quality Standard

Rhodonite – Quality Standard

Rosophia – Quality Standard

Semper Fi – Quality Standard

Serpentinite – Quality Standard

Tourmaline in Quartz –

Quality Standard

Unakite – Quality Standard