glass plate, 2" x 2" with sanded edges
Useful in testing mineral hardness. Glass is 5 1/2 on the Mohs' scale of mineral hardness, so if your mineral scratches glass, it is harder that that. Orthoclase feldspar is 6 and quartz is 7 on that scale.
We sell these in sets of five for $3.50, but also list them as single plates for those who need just one or two and are ordering with other specimens.
Making multiple purchases? Click on the "combine shipping" button in the shopping cart. We'll send an invoice with combined shipping. A link in that invoice will bring you back to checkout, no hassle.
Ships free with other items.