PhotosStrontianite - Inverhuron, Bruce Township, Bruce Co., Ontario, Canada
Curious about the curved shape of the strontianite from this locality - we have a sample with similarly-shaped crystals - some are acutely curved - reminds me of of scythes, or cat claws.
Is there an explanation for this growth habit?
Maggie
I don't know the science behind the curvature, but the strontianite from Convict Hill. Austin, Texas is also strongly curved. My catalogue lists the specimens I collected many years ago but I can't find the specimen to photograph!!! I know I collected an entire pocket from the limestone bluff - 2 hours of chiseling - maybe the specimen escaped back to Convict Hill ??!!
Don 
The strontianite gallery on Mindat shows curved crystals from Kentucky, Pennsylvania and Virginia in the US. This habit appears to be somewhat common, at least in this hemisphere. 
looking through the Mindat galleries, it appears common in other parts of the world, too
Austria
Germany
Italy
Here's a shot of another Inverhuron Strontianite.
Analysis of such strontianites often shows them to contain minor Ca. Thus, there is a possibility that zonation causes distortion involving adjacent unit cells, resulting in curved crystals (compare curved dolomite-ankerite-..., curved members of the pyromorphite-mimetite-vanadinite group and others). AFAIR there is some older literature on these features.
Inverhuron, Kincardine Township, Bruce County, Ontario, Canada