It's considered vitreous in luster and has a Mohs hardness of around 5.5. Unless it's stained with copper oxide, it has a clear to white color and a specific gravity of 2.2 to 2.4 respectively. It can be found in fracture fillings of basalt or nodules found within the trap basalt along with similar zeolite minerals.
It's often confused with Thomsonite as it closely resembles the "eye" pattern but remains separate by definition. In general it has softer looking colors and patterns, where as Thomsonite has well defined circles and lines with less radiating fan-like design.