Now, as an amateur geologist (rockhound really) I can't say for sure if this block of mostly black stone is really obsidian. I am ready to be schooled.
1) vitreous. It has veins of calcite (they scratch with a knife). From what I can see of the native stone through small flakes, it is very glassy, though overall dulled, I presume from water wear.
2) between 3.5-5.5 on the mohs scale. Penny wont scratch it, steel knife does a nice job.
3) fairly heavy. sg not available
4) streak is clear
5) non magnetic.
6) the size is about 4"x4"x2"
1) vitreous. It has veins of calcite (they scratch with a knife). From what I can see of the native stone through small flakes, it is very glassy, though overall dulled, I presume from water wear.
2) between 3.5-5.5 on the mohs scale. Penny wont scratch it, steel knife does a nice job.
3) fairly heavy. sg not available
4) streak is clear
5) non magnetic.
6) the size is about 4"x4"x2"
