There is no set location at Level 5 it will be random loot from dungeons and at Level 6 it will be sold from vendors. Best dungeons to look for them in are Necromancer and Conjurer dungeons.
Also, you can just steal one from any store (assuming that the store has one on display for you to actually take). Just make sure the shopkeeper isn't looking.
get yourself up to at least lvl 20, then go and search the mythic dawn's base. You will find it there.
Try Pestle as in Pestle and Mortar
The mortar is a bowl-shaped container used to hold the ingredients, while the pestle is a heavy tool used to crush and grind the ingredients in the mortar. The pestle is typically a heavy and blunt object, while the mortar is a bowl with a smooth interior.
http://www.phisick.com/images/apoth/mortar-and-pestle-brass-101.jpg
Chemicals are ground into powder using a mortar and pestle.
The word pestle is generally used in connection with the word mortar. It is from Latin pistillum, an instrument used for crushing; the mortar is a kind of bowl, and the pestle is used to crush a substance to powder in the mortar.
A mortar and pestle made of glass is typically used for grinding and crushing substances into fine powders or pastes. It is commonly used in laboratories for grinding chemicals or in kitchens for grinding spices and herbs. Glass mortar and pestle are preferred for their non-reactive nature and ease of cleaning.
for powdering...
A mortar and pestle are used to grind substances into smaller particles.
Pestle.
mortar and pestle
When using a mortar and pestle, ensure it is clean and dry before use. Be cautious when grinding harder ingredients to prevent damage to the mortar or pestle. Be mindful of cross-contamination by thoroughly cleaning the mortar and pestle between uses, especially when switching between different ingredients.