Quality Standards for Cabochons
Quality standards for cabs
Nowadays the global market for cabs is flooded with cheap cabs of low quality from mass production countries like China, India, Pakistan, Madagascar etc. It is getting harder and harder to explain to the end consumer the price differences so they can appreciate quality and distinguish high value products from cheap or even fake mineral cabochons.
Here you can find detailed information about how cabochons from Gemrock Peru stand out.
The Basics: Parts of cabochons
A cabochon consists of three parts: Dome, Bevel and backside
There are a number of dome types:
Disk – does not have a dome
Buff top or Flat dome
Very high dome
As a general tendency one can say that Low quality cabochons show medium to very high domes, while high quality cabochons and designer cabochons tend to show buff tops. We can cut any of the dome types for you but recommend flat domes in order to position your cab in the right group.
The Basics: Parts of cabochons
There are a number of bevel types too:
No bevel at all
Regular straight single bevel
Inclined single bevel
As a general tendency low quality cabochons display regular straight single bevels. High quality and designer cabochons can display regular straight single bevels but often stand out from the crowd by displaying inclined single bevels. Double bevel cabochons are very rare to find and definitely a sign of mastership and exclusivity. Gemrock Peru can cut any bevel for you. Our own designer cabs are generally are cut with a inclined single bevel.
Mass finish or hand-made
Sometimes you can find cabs, being displayed together in great numbers that don’t show any bevel but are rounded all over.
Those cabs have been mass-finished in a tumbler. The tumbling process rounds the stone on all sides and makes it impossible to show a bevel. Those are the cheapest of cheap cabochons. Gemrock Peru does not produce such items. All our cabochons are made by hand and one by one.
How to recognize quality?
Cheap cabochons are never polished on the back side. We give our clients the choice to order regular cabochons where the backside is not polished or to opt for a polished back. A polished backside is of advantage if you are a wire artist or if you want to set your stone in silver or gold with an open setting that does not have a complete backside. As a general rule our own designer cabs are polished on the backside.
Have a look at the bevel and you can immediately tell the difference between low and high quality.
On a cheap cabochons you can find all kinds of flaws:
- The bevel is not polished or is not polished to the same level as the dome.
- The bevel edges are not straight but irregular and or wavy
- At the cabochon corners the bevel gets smaller, displaying a dropping corner.
- The bevel edges are not sharp and crisp but rather rounded.
- The edge between bevel and backside is serrated or chipped off.
A high quality cabochons displays a bevel:
- That is polished perfectly
- That shows a perfectly straight bevel
- That maintains the same bevel height at the corners
- That shows very sharp and crisp bevel edges on both upper and lower edge
- That shows a lower bevel edge with the backside that has no irregularities, chipping holes or other flaws.
Cabochons are coming in all kinds of shapes. As general rule cheap cabochons mostly come in classical shapes like ovals, drops, etc. Designer cabochons mostly display complicated, irregular and out of the order shapes.
Whatever shape a cabochon displays, if the shape is flawed and irregular, it’s a very cheap one:
Cheap low quality cabochons can be easily identified by displaying on or several of the following flaws:
Low quality polish: light reflections on the dome are showing opaque borders
Irregular dome with dents and bumps or showing small flattened areas (especially at the corners and aside the bevel edge).
Scratches: The early stages of shaping the dome are made with big grit diamond grinding wheels. They do leave scratches on the surface that have to be eliminated when working with higher grits. If that is not done well the cabochon may result with a perfect polish but still displays scratches which can be identified as short whitish scratches, often two or more straight parallel lines).
Holes: Cheap cabochons show holes when made off low grade materials (We do not refer to natural druses holes)
High quality cabochons are characterized by:
Excellent polish to be recognized by crisp sharp light reflections
Scratch free: At Gemrock Peru we have a rigorous policy on scratches. Each cabochon is checked with a magnifying glass for scratches before it moves up to the next polishing step. If any flaw in shape or surface is detected it goes back to the previous step to be corrected.
Excellent shape with no bumps, dents or flat areas.
Last but not least: materials
We at Gemrock are not arrogant about materials. There are many cheap natural materials that produce excellent amazing cabochons. We ourselves are producing cabochons from hand-selected beach pebbles with great results.
However there are some materials like Chrysocolla, Pink Opal and others that come with very different rough material qualities and for those materials must be said that if you chose a cheap low grade material than it is just not possible to expect a high quality cabochon to come out of that.
At Gemrock Peru we will provide you with expert advice on how to choose you rough materialsand we will explain you beforehand what results you can expect with what material.
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