This depends on what you plan on using it for. No right answer, some are for liquids, some designed for solids, hard spices and seeds vs nuts or herbs.
Metals such as iron or brass tend to be non-porous, smooth, great for chemicals, pills. Too smooth for hard spices and require special care, but look impressive.
Wood is soft and porous, absorbs flavors, so it is bad for seeds, strong spices but good for nuts, fresh herbs. Like when making pesto, or serving oil bases sauces.
Glass and Porcelain are a bit harder, non-porous, not as heavy as hard as stone, but 1/4 to 1/2 the weight of a stone one the same size. Easy to wash, light, good for herbs, nuts, making pestos, sauces, serving.
South American Molecajete are made from porous lava rock, unless you buy an really high quality one (and even cheap ones are very costly) they tend to be too porous and chip off into your food. Don't recommend getting one except to serve or decorate.
Stones such as granite and marble are the hardest and heaviest. Grinding seeds, pills, herbs, but can be slippery for liquids, splash ingredients. Their weight makes them bulky and impractical, but my personal preference for versatility.
If the petals are dried, the best way to grind them is with a mortar and pestle. Add the water in very small amounts, mixing with the pestle.
Pestle is both a noun (the object) and a verb (an action) "to pestle" is to grind or pound as if with the object.examples:Her thoughts were pestled by the constant interruption of Darryl and his obnoxious yappy dog.You should pestle that before brewing, she said with a smile.Hand me that pestle, would you?The vessel with the pestle has the brew that is true.This mortar needs a finer pestle.My other pestle is on the trestle.
That is a mortar and pestle.
When used in in the grinding of materials for chemical applications, the pestle is generally made out of ceramic or a chemical resistant type of stone; more so the former rather than the ladder. Pestles are also made of a many number of materials, but not usually for the use of chemistry as the it may react with the the ground material.
You use pestle and mortar on your item.
Use them on a Pestle and Mortar.
The dictionary definition of a pestle is: a heavy tool with a rounded end, used for crushing and grinding substances such as spices or drugs, typically in a mortar. In other words, a pestle is use to grind small quantities of substances into a powder.
There are many material you can use. The best material is fiberglass, but metal and wood are good substitutes.
A mortar and pestle
There is no best material to use to make sheer draperies. It is a matter of taste. I personally like to use a fine silk.
What you can use is a rolling pin with the onion in a zip-lock bag or freezer bag or food process it really fine and then bash it
You use a Pestle & Mortar, you can get this from Herblore shop in Taverly.