Qualifying Child. To be considered a qualifying child, your grandchild must be under the age of 19 on the last day of the tax year, or if he's a full-time student, under the age of 24.No age restrictions apply, however, if your grandchild is permanently and totally disabled.ualifying Child. To be considered a qualifying child, your grandchild must be under the age of 19 on the last day of the tax year, or if he's a full-time student, under the age of 24.
Platinum-iridium alloy. Platinum-iridium alloys are alloys of the platinum group precious metals platinum and iridium. Typical alloy proportions are 90:10 or 70:30 (Pt:Ir). These have the chemical stability of platinum, but increased hardness. The Vickers hardness of pure platinum is 56 HV while platinum with 50% of iridium can reach over 500 HV.
Ask your jeweler about the alloy used in your platinum ring. If you are buying a pure platinum ring (95% platinum), then it should be alloyed with either Cobalt or Ruthenium. These alloys produce a harder platinum that can hold a mirror bright polish and resist years of daily wear.arnings. 1  If your platinum ring needs to be repaired, be sure to take it to a master platinum-smith. 2  If you are interested in buying an antique platinum ring, it will probably bear the hallmark IridPlat or .90Plat/Ir on the inside of the band.