It's unlikely caused by a scratch because of its shape. A close up picture shows this possible mark.
The decanter is in excellent condition. The shot glasses are about 3-1/8 inches tall.
One of the shot glasses has a defect which to me appears to be a manufacturing flaw or a glaze skip. On the outside of this area (see closeup picture), it feels kind of like a chip, but on the inside it is smooth but there is no cobalt blue glaze. The item "COBALT BLUE DECANTER EXQUISITE CUT GLASS WITH 4 SHOT GLASSES" is in sale since Tuesday, September 06, 2016. This item is in the category "Pottery & Glass\Glass\Art Glass\Bohemian, Czech\Other Bohemian/Czech Art Glass". The seller is "reliques" and is located in Canton, Connecticut. This item can be shipped to United States, to Canada, to United Kingdom, DK, RO, SK, BG, CZ, FI, HU, LV, LT, MT, EE, to Australia, GR, PT, CY, SI, to Japan, to China, SE, KR, ID, to Taiwan, ZA, TH, to Belgium, to France, to Hong Kong, to Ireland, to Netherlands, PL, to Spain, to Italy, to Germany, to Austria, RU, IL, to Mexico, to New Zealand, PH, SG, to Switzerland, NO, SA, UA, AE, QA, KW, BH, HR, MY, BR, CL, CO, CR, PA, TT, GT, HN, JM, AG, AW, BZ, DM, GD, KN, LC, MS, TC, BB, BD, BM, BN, BO, EC, EG, GF, GG, GI, GP, IS, JE, JO, KH, KY, LI, LK, LU, MC, MO, MQ, MV, NI, OM, PE, PK, PY, RE.