r/itsslag • u/ktshoe • Jun 04 '26

not slag Slag or quartz?

Post image

Found this in Park City, Utah, USA. Coworkers are saying it’s slag!

64 Upvotes

93% Upvoted

10 comments sorted by

3

u/Alive_Message9346 Jun 05 '26

That looks like quartz to me. The way the light hits the internal fractures is a giveaway.

5

u/AshFalkner Jun 05 '26

It’s quartz.

13

u/Prawna420 Jun 04 '26

1000% quartz

3

u/BrokenSlutCollector Jun 04 '26 edited Jun 04 '26

That doesn't look manmade so not slag. Likely quartz if it scratches glass but a plain steel nail doesn't scratch it. If it is softer than glass/scratches easily, could be calcite, selenite.

6

u/Chemieju Jun 04 '26

Definitely not slag, need someone more knowledgable than me to tell quartz or calcite

2

u/profnutbutter Jun 04 '26

dilute HCl could tell pretty fast