Can someone explain crystalization in silver coin?

[Scotvs Capitis]

I've had my eye on a couple of imperial denarii for a long time, the dealer notes that they have crystalization, and is up front about it. They have a slight frostiness but overall look attractive, and for what my budget allows, could fill an important slot in my collection. I am wary though, crystallization can't possibly be good. I have dealt with bronze coins in my uncleaned coin exploits that sometimes seem to have degraded to a granular matrix and become brittle. I discovered this when I dropped a superbly cleaned and nearly perfect Aurelian Antoninianus on the floor once and it shattered into several pieces, breaking my heart in the process. Is silver crystalization a similar phenomenon?

I searched the forum and read what little there was on crystalization, but I'm wondering if there is a better answer, or if I should avoid a crystalized coin altogether.

[moonmoth]

Scott - My page might be helpful.  If it isn't, please let me know in what way I can improve it!

https://www.forumancientcoins.com/moonmoth/crystal_coins.html

I haven't seen crystallisation in bronzes, though I have seen a coin with so much leached away that just a light matrix is left.  If you are prepared to relinquish ownership of the pieces of your shattered Aurelian, I would be interested in making an offer.

In a denarius, crystallisation might not be much of a problem.  It will affect the surface appearance, particularly in close-up, but the coin might be fine otherwise.  On the other hand, it might also make the coin very weak and brittle.  I suspect the only way to find this out is a destructive one!

[Scotvs Capitis]

Thanks! Excellent link, thanks for the investigation. Very thorough. I also enjoyed the Haristyles of the Rich and Famous page and some others. Linked you up to my blogroll as well.

I may go ahead and get one of the two coins I have my eye on, if only to see how severe the crystalization is.

[moonmoth]

Thanks.  I have to update my own links page.  There are a lot of sites worth adding.

If you find out anything interesting about the coins, please post it! 

One other thing I can add.  The weakest crystallised coin I have come across was the Sasanian drachm shown on my page.  It broke like a thin biscuit.  That had quite a matt surface effect, more so than other crystallised coins, and seemed slightly off-white.  Perhaps that goes with the weakening.  Or perhaps not .. more data needed ...