Depends on what you want to do with them! This is from the book The Sacred Herbs of Samhain:
And according to the Llewellyn 2020 Sabbats Almanac (last year’s), stones that are appropriate to use in your Samhain festivities include all colors of calcite, fire opal, all forms of jasper, jet, hematite, moldavite, andtektite, obsidian.
Like Megan said, there are some more correspondences here: How to Celebrate Samhain: Rituals & Ideas! 💀