A friend of mine gave me few chunks of stones a year ago. I have no idea what kind of stone he gave me by that time. I made a little amateur research myself about the stones, and judging by its appearance I temporarily decided that the stone is some sort of pyrite stone - some sort of mineral stone.According to the history In the old days pyrite stones are used as a jewelry engraving thus it has a very small economical value.
Last month I decided to bring the stones to the local gemstones smith, the smith identify the chunks as 'Pancawarna' stones as it has five different color. I search Google and found out that Pancawarna is an Agate stone