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Techniques for CollectorsInternal crystal fractures

16th Dec 2015 01:48 UTCBob Harman

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The pictured calcite crystal on dolomite example, formerly in my collection and now in the possession of the Indiana State Museum, represents an example of numerous crystals I have self collected with crystals showing internal fracturing. I see these commonly in calcites, barites and fluorites among other commonly collected species. This crystal is perfect, showing no cracks, dings, chips or other evidence of damage, but is obviously internally fractured. Commonly, very careful examination of these crystal surfaces shows no evidence of the cracks reaching the surface, but if an example such as this was dropped, it is likely that any damage, such as cracking of the crystal, might occur along one of the internal fracture planes.

So my questions involve these visible internal fracture planes; in and of themselves, do they affect a specimen's value? And in high end examples of any mineral specimens can they be treated to minimize their appearance, even tho they don't reach the crystal surface? Any help with this?? CHEERS.......BOB

16th Dec 2015 04:55 UTCJohn Attard Expert

Bon, I think that any cracks even if natural and do not reach the surface affect the specimen value negatively.


Any attempt at covering it up, strengthening it or anything is also detrimental. All you can do is to protect it especially from thermal shock. Once I saw at Tucson a mineral dealer unpacking a large lot of impeccably faceted clear transparent calcite crystals that had stood a cold flight from Brazil. Unfortunately it was rather late before he realized that all his crystals were developing internal fractures as he put them on the display shelf. There was a "feeding frenzy" with buyers asking "let's see some more". He should probably have kicked everybody out and waited till the lot has equilibrated to room temperature while still packaged.


Bob that is a nice piece!

16th Dec 2015 15:37 UTCRob Woodside 🌟 Manager

Consider an "ice cube" Dalneagorsk fluorite or a Big Rig calcite. Do you think some one would pay more for one without any internal fractures? In a New York minute they would!!!


Just as jewelers want clean gemstones so do mineral collectors.
 
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