Last March, Jim Rienhardt brought his collection of some 270 sands to the WCGMC meeting and told us about arenophiles (sand collectors) (Reinhardt, 2018). Jim repeated his presentation at the Rochester Academy of Science later that month. At that meeting RAS member Paul Dudley brought along some sand he had collected from Hamlin State Beach some 50 years ago. Paul’s sand was red and dominated by garnet, but full of other heavy minerals. He told us that the sand had been collected during a college field trip late in the spring when Lake Ontario first started to recede from winter highs.
I parked that in my memory and on my calendar and on July 8th set out to find some “garnet” sand for myself. I was not disappointed. The first stop I made was at Area #5 at the west end of Hamlin State Beach. The Lake level seemed to have dropped, perhaps a foot from its highest erosional cut. And in the bank left when the lake level was highest was a 2-3 cm thick band of black and red sand. I sampled and took pictures and moved to other areas of the park.
We do a lot of different things at WCGMC meetings and on workshop Saturdays. I don’t often document these activities to my blog as I don’t think they would generally interest folks outside the club. But at the June meeting this year we did something a little different and I decided my newsletter note for the July newsletter served to be placed here. You see we made garnets …. well, sort of.
Porphyroblast: I’ve always thought that was such a neat word, maybe even interesting enough for a story. Say it out loud three times (“pore-fur-o-blast, pore-fur-o-blast, pore-fur-o-blast”). Now don’t you want to learn more, perhaps even own a few?
Porphyroblasts are those large recrystallized minerals that grow in the groundmass of a metamorphic rock, most typically in schists and gneisses. In New York State, we immediately think of the bright red almandine-pyrope garnets in the gneissic rocks in the Gore Mountain area, but the truth is the metamorphic schists and gneisses throughout New York and New England often contain garnet porphyroblasts. Unfortunately a lot of New York’s garnets are hosted in high-grade metamorphic gneiss and they don’t display crystal faces when the rocks are broken. Nevertheless they are large, colorful and fun to collect.
Last month I wrote about the Arkansas portion of Wayne County Gem and Mineral Club’s November field trip south (quartz, quartz and more quartz). But we did not stop there. After three days of collecting SiO2 in and around Mt. Ida, Arkansas, ten of us pointed our large black van east and headed to Tennessee and North Carolina. There was still a bit of space to fill in the van and in the trailer and we simply could not head north without filling all possible nooks and crannies. Here is how we did it! Continue reading
Garnet mining in New York State dates back to the late 19th century when the Barton Mine first opened in 1879. Henry Barton experimented with garnet as a harder and more durable abrasive than simple sand and after a fisherman friend told him about the prolific garnets in the Adirondacks he staked his claims and went into production (Kelsey, 2015).
Wayne County Gem and Mineral Club has decided to make 2016 the year of the Birthstone. And isn’t garnet a great way to get started!
Garnets are hard (Moh’s hardness of 6.5-7.5), or as hard or harder than quartz. As members of the isometric crystal system garnets are symmetric with three equal and perpendicular axes. Garnets are colorful: red, yellow, green and many shades of each. And garnet is the birthstone for all born in January.