These are Madagascar petrified wood palm stones.
Petrified wood is an ancient wood that has morphed into a mineralized fossil stone through the process of permineralization and replacement.
It goes through long stages of poetic and beautiful metamorphoses to form over time. Originally, wood fibers and other plant matter are covered by sediment and prevented from decaying. Groundwater full of dissolved minerals and mineraloids such as opal, calcite, pyrite, and silica eventually replace the plant material and these materials crystalize over millions of years. This is why the new composition is called a fossil, because it has a preserved plural makeup of the original resin and plant materials along with various mineral and mineraloid deposits.
Petrified is very popular among artisans for making jewelry, carvings and decorative vessels.
It is said be tied to the root and sacral chakras and embodies earth energy.
Because this ancient wood has slowly turned into stone over millions of years, thus going through great, steady and deep transformation, the stone is said to represent meaningful change, spiritual transformation, psychic shifting, patience, resilience and sagacity.