80g-120g Optical Calcite Iceland Spar Mineral Healing Raw Stones Rough Rock Crystals for Tumbling,Cabbing - Bulk Mineral

This optical calcite is perfect! Nice, thick chunk and crystal clear. My video doesn’t capture how beautiful it truly is but I at least wanted to show the double refraction and nice size. Thank you!!

Seems like a really good chunk of crystal. Nice large piece. Mine is pretty clear too. Good value

Decent sample. Not quite as clear as I would’ve liked.

I bought this because I like stones and rocks! This is a piece of history.That was used for mariners, many, many years.Ago I love having it in my collection.I love it must have for anyone that likes rocks.Fossils etc...

Beautiful! Very clear and just the right size.

I am very torn by this product. I wish that I could recommend it. But it is very opaque, impossible to see through and does very littler to show the optical qualities that give it, its name. In this quality these are little more than novelty paperweights, which in that sense they are quite nice. But thinking of using this for a teaching tool? Or as a romantic gift to use as a sunstone? No. Look elsewhere. They aren't high enough quality to be functioning.

It was a little cloudy than I expected. I have a couple of other specimens, and this is by far the cloudiest piece that I have so I’m a little disappointed, but I was pleasantly surprised at the size, so that kind of makes up for it.

This was advertised as optical quality, and that was delivered. If you look at the photo you can clearly see the birefringence (light passing through calcite is split along two paths, forming a double image on the far side) even though the photo was taken indoors under normal room lighting. I was looking for a crystal like this to use as a Viking Sunstone. The required clarity and size are both there (the ruler photographed is scaled in inches). The crystal was very carefully packaged for shipping, as well. Lots of paper wadding inside a well taped and plastic shrink coated cardboard box. Thank you!