1. Ore market or ore wholesaler: Some large ore markets or wholesalers will sell various types of ores and precious stones, including volcanic rocks. You can go to the local ore market or contact the ore wholesaler to see if there is any supply of volcanic rocks.

2. Jewelry shops or gem shops: Some jewelry shops or gem shops may also sell ornaments or rough stones made of volcanic rocks. You can go to the local jewelry store or gem store and ask if there are any volcanic rocks to buy.

3. Online shopping platforms: Taobao, JD.COM, Amazon and many other online shopping platforms have all kinds of precious stones and ore products for sale. Search for products related to volcanic rocks and choose reliable merchants to buy them.