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Improving Mindat.orgHowlite MOH error

6th Jun 2011 16:56 UTCFletch Waller

I believe there is a typo or error on your specs page for Howlite -- min-1936/html. You show hardness at 6 -6.5 while all other linked sources show MOH 3.5. My specimen tests at 3.5. This FYI and review?

6th Jun 2011 17:24 UTCRob Woodside 🌟 Manager

Fixed Thanks.

6th Jun 2011 17:38 UTCAlfredo Petrov Manager

I think the 3.5 hardness was for the massive nodular masses and the much harder value was for individual crystals like the ones from Iona, which is the true mineral hardness rather than the aggregate's friability.

6th Jun 2011 17:59 UTCRob Woodside 🌟 Manager

I wondered about that. The Nova Scotia xls could tell the difference but I haven't any to sacrifice.

6th Jun 2011 18:57 UTCDavid K. Joyce Expert

About 15 years or so ago, Dr. Robert Gait of the Royal Ontario Museum and I noticed that the hardness of the howlite crystals that I had collected at Iona, Cape Breton Island, Nova Scotia was much harder than the published hardness in all textbooks. The Iona locality is the only locality that I know if that produces large crystals (to 18mm or so) that are suitable for hardness testing. Dr. Gait, conducted an "official" hardness test using equipment at the Royal Ontario Museum and arrived at the 6.5 hardness. We concluded that previously, hardness tests had probably always been conducted on nodular masses of howlite which will always give a lower hardness. We presented a paper on the Iona Howlite at the Rochester Academey of Sciences Symposium in Rochester(1993) and the abstract was subsequently published in Rocks and Minerals Magazine. I have written an article about the locality and it can be viewed at http://www.davidkjoyceminerals.com. Look under "Articles".


I'd appreciate it if you could keep the hardness of howlite at the higher level on mindat.org based on the work that we did!


Regards,

David K. Joyce

6th Jun 2011 19:03 UTCRob Woodside 🌟 Manager

Thanks so much Dave. I'll fix it.

7th Jun 2011 00:12 UTCAlfredo Petrov Manager

Yet again, Mindat was right and the print references were wrong. (Sorry, couldn't help gloating :)

7th Jun 2011 00:23 UTCRob Woodside 🌟 Manager

Alfredo, at least some one at Mindat was paying attention to Rocks & Minerals.;)
 
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