When you use the sorting feature in storage (for example, sorting a chest), the items will be sorted based on their sorting priority in ItemID.Sets.SortingPriorityMaterials[]. When making a custom item, this value is set inside of SetStaticDefaults(), using ItemID.Sets.SortingPriorityMaterials[item.type] = XX (requires using Terraria.ID;).

For example, if you wanted your item to have the same sorting priority as a platinum bar (Item ID: 706), which has a sorting priority of 59, you would write this in SetStaticDefaults():

ItemID.Sets.SortingPriorityMaterials[item.type] = 59;

Here is a full list of vanilla sorting priorities, according to item ID (anything not on the list has a value of -1):

• (Item ID: Sorting Priority)
• 11: 48
• 12: 44
• 13: 56
• 14: 52
• 19: 57
• 20: 45
• 21: 53
• 22: 49
• 56: 62
• 57: 63
• 86: 64
• 116: 60
• 117: 61
• 174: 69
• 175: 70
• 177: 39
• 178: 41
• 179: 40
• 180: 38
• 181: 37
• 182: 42
• 364: 77
• 365: 81
• 366: 85
• 381: 78
• 382: 82
• 391: 86
• 520: 71
• 521: 72
• 547: 75
• 548: 76
• 549: 74
• 575: 73
• 699: 46
• 700: 50
• 701: 54
• 702: 58
• 703: 47
• 704: 51
• 705: 55
• 706: 59
• 880: 65
• 947: 90
• 999: 43
• 1006: 91
• 1104: 79
• 1105: 83
• 1106: 87
• 1184: 80
• 1191: 84
• 1198: 88
• 1225: 89
• 1257: 66
• 1329: 67
• 1508: 93
• 1552: 92
• 3261: 94
• 3380: 68
• 3456: 97
• 3457: 96
• 3458: 98
• 3459: 95
• 3460: 99
• 3467: 100