I custom cut this focal bead out of genuine, natural, untreated Persian turquoise that was mined in the 1970's. It has a 2.5mm drill hole and the dimensions are in the listing title in millimeters. CHAIN NOT INCLUDED. I bought a few pounds of this turquoise as rough from a very reputable mineral dealer from Canada. I have bought rocks from them regularly for years at the trade shows in Tucson. The dealer got it from a college in Ontario. A Canadian diplomat, who loved turquoise, was stationed in Persia and brought home a few hundred pounds of this rough turquoise in the 1970's. This diplomat left his estate to his alma matter when he died. When the college got it's hands on this turquoise they sold it directly to the mineral dealer I got it from. Thus the rough I used to cut these stones has very good, direct, provenance and I have complete faith that this is, in fact, natural, untreated, Persian turquoise from the source. The United States has banned all direct trade for the last 40 years so it is very difficult to get genuine cutting rough like this. The rough I got is consistent and the colors run from the classic robin egg's blue to a soft, minty green color. Turquoise has been mined in Persia for 4,000 years! The word turquoise is the French word for "Turkish" and since antiquity Europeans have gotten Persian turquoise through Turkey or Turkish merchants. That's how it got the name we know it by. Check out the rest of my listings for more focal beads and cabochons in this rare gemstone.