glass plate, 2" x 2" with sanded edges - student unit of 5
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 than that. Orthoclase feldspar is 6 and quartz is 7 on that scale.
We normally sell these in sets of five for $3.50, but also have them listed them as single plates for those who need just one and are ordering it 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.