Here is a little something I made to sell in my shop. It is a sandstone altar tile with engraved pentagram and ivy motif. The sandstone piece is 6in. square, and about 1 1/2 in. high. It is beveled (smaller at the base, and widening at the crown) and is slightly concave on top. I think it was supposed to be some sort of candle holder originally. I picked it up on clearance, and thought I could do something with it.
I drew the pentagram and the ivy design by hand sing a pencil. Then I went over it with a diamond burr on my Dremel tool. It took several hours to complete (I wasn't really in a rush), and just about wore out the burr. It was labor intensive and time consuming enough that I don't plan to make any more like this, even though I have two or three more sandstone blanks. I have a short attention span, and bore easily. That's why many of my projects take months, or years to complete. I start on them, then get bored and set them aside, leaving them half finished. This one was right at the edge of what I can do in one sitting.