Peridot belongs to the forsterite-fayalite mineral series which is part of the olivine group. It is one of the idiochromatic gems, meaning its color comes from the basic chemical composition of the mineral itself, not from minor impurities, and therefore will only be found in shades of green. In fact peridot is one of the few semi-precious gemstones found in only one color.
They have highly sensitive blood tests that can detect the pregnancy hormone (hCG) a few days earlier around day 3 to 4 after implantation. Again, some women have had positive urine tests as early as 2 to 3 days after implantation and others have had to wait up to a few weeks.
You can take the pregnancy test about 3-4 days after signs of implantation or about a week afterward, after you've missed your period. Implantation bleeding usually lasts about one or two days, and in rare cases it can last a month or two. If you are experiencing extreme pain during bleeding or the color of the blood has turned a deep red, then you need to consult a health care specialist, your mid-wife or family doctor.