Corundum specimens with trigonal growth patterns

Small crystals of Corundum showing off characteristic trigonal growth patterns.

These crystals all measure 5-10MM with an average weight of 4ct or 0.8 grams.


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Corundum specimens with trigonal growth patterns

Bit of a mouthful, that title... but, yes, these are small crystals of Corundum showing off characteristic trigonal growth patterns.

These crystals all measure 5-10MM with an average weight of 4ct or 0.8 grams, and come from Madagascar.

For mineral collectors and anyone interested in crystallography or how crystals form, these are quite interesting - for others, they may best be described as 'corundum with triangles'.

The small triangular formations on the terminations of the crystals are called 'trigons', and are related to how the crystals grow. It is somewhat difficult to find an easy to digest scientific paper on these patterns but there is some information on their appearance on rough diamonds available here which is informative. 

Frequently asked questions and delivery information

How do we grade stones?

There is no overall universal grading system for the majority of our products. As such, the grades we use are internal only. They simply refer to higher and lower qualities, but they may be entirely different grades to other websites. C grade pieces are of lower quality than B grade, which is lower than A grade.


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I get tracking information etc online when this has been completed. I typically do not send tracking information to customers unless they request it – but if you’ve requested tracked postage, it has been sent tracked! If you have any worries or concerns about your parcel being delayed please feel free to get in touch and I’ll send the tracking info over! We also get delivery confirmations for parcels over 25MM thick by default.


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