Agate

Dear Ernst

You have mentioned Agate as a multi Color stone for Venus (Venus in Capricorn). In Iran we have Agate in many colors . Pure yellow, Red, Brown ....

Can we use these for Venus in other Rashis?

I was confused to find out that all other Venus Stones have Trigonal Crystal System but
Agate has Rhombohedral Crystal System which Wikipedia indicates they are not the same.

Also Quartz has both Trigonal and Hexagonal Crystal systems which makes me wonder how can we make sure a Quartz crystal is Trigonal for Venus. Dose it make a difference at all?

Thanks