diff --git a/src/fragmentarium/domain/Fragment.test.ts b/src/fragmentarium/domain/Fragment.test.ts
index 386675882..8a6b57b6a 100644
--- a/src/fragmentarium/domain/Fragment.test.ts
+++ b/src/fragmentarium/domain/Fragment.test.ts
@@ -42,6 +42,7 @@ const config: Parameters<typeof Fragment['create']>[0] = {
         note: '',
         legacyData: '',
         isInFragmentarium: true,
+        isEnvelope: true,
       },
     ],
   ],
diff --git a/src/fragmentarium/domain/join.ts b/src/fragmentarium/domain/join.ts
index 8b705e6a5..71dc7b502 100644
--- a/src/fragmentarium/domain/join.ts
+++ b/src/fragmentarium/domain/join.ts
@@ -6,6 +6,7 @@ export interface Join {
   readonly note: string
   readonly legacyData: string
   readonly isInFragmentarium: boolean
+  readonly isEnvelope: boolean
 }
 
 export type Joins = ReadonlyArray<ReadonlyArray<Join>>
diff --git a/src/fragmentarium/ui/info/Details.test.tsx b/src/fragmentarium/ui/info/Details.test.tsx
index 350219f61..b3cafbfc7 100644
--- a/src/fragmentarium/ui/info/Details.test.tsx
+++ b/src/fragmentarium/ui/info/Details.test.tsx
@@ -77,6 +77,7 @@ describe('All details', () => {
             [
               joinFactory.build({ isInFragmentarium: false }),
               joinFactory.build({ isInFragmentarium: true }),
+              joinFactory.build({ isEnvelope: true }),
             ],
           ],
         },
@@ -101,6 +102,12 @@ describe('All details', () => {
     ).toBeInTheDocument()
   })
 
+  it(`Renders envelope icon for joins`, () => {
+    expect(screen.queryAllByLabelText('envelope icon').length).toBeGreaterThan(
+      0
+    )
+  })
+
   it('Does not link to self', () => {
     fragment.joins
       .flat()
diff --git a/src/fragmentarium/ui/info/Details.tsx b/src/fragmentarium/ui/info/Details.tsx
index 5b8511514..698270428 100644
--- a/src/fragmentarium/ui/info/Details.tsx
+++ b/src/fragmentarium/ui/info/Details.tsx
@@ -44,14 +44,17 @@ function Joins({ fragment: { number, joins } }: Props): JSX.Element {
                 className="Details-joins__join"
                 key={`${groupIndex}-${index}`}
               >
-                {index > 0 ? (
-                  <>
-                    <br />+{!join.isChecked && <sup>?</sup>}
-                  </>
-                ) : groupIndex > 0 ? (
+                {index > 0 || groupIndex > 0 ? (
                   <>
                     <br />
-                    (+{!join.isChecked && <sup>?</sup>})
+                    {join.isEnvelope ? (
+                      <i
+                        className="fa fa-envelope"
+                        aria-label="envelope icon"
+                      ></i>
+                    ) : (
+                      <>+{!join.isChecked && <sup>?</sup>}</>
+                    )}
                   </>
                 ) : (
                   ''
diff --git a/src/test-support/join-fixtures.ts b/src/test-support/join-fixtures.ts
index 516f140e1..612a055be 100644
--- a/src/test-support/join-fixtures.ts
+++ b/src/test-support/join-fixtures.ts
@@ -21,6 +21,7 @@ export const joinDtoFactory = Factory.define<
     note: chance.sentence(),
     legacyData: chance.sentence(),
     isInFragmentarium: chance.bool(),
+    isEnvelope: chance.bool(),
   }
 })
 
@@ -32,4 +33,5 @@ export const joinFactory = Factory.define<Join>(({ sequence }) => ({
   note: defaultChance.sentence(),
   legacyData: defaultChance.sentence(),
   isInFragmentarium: defaultChance.bool(),
+  isEnvelope: defaultChance.bool(),
 }))
diff --git a/src/test-support/test-fragment.ts b/src/test-support/test-fragment.ts
index 59dd5d457..fd65dbe91 100644
--- a/src/test-support/test-fragment.ts
+++ b/src/test-support/test-fragment.ts
@@ -342,6 +342,7 @@ export const fragmentDto: FragmentDto = {
         note: '',
         legacyData: '',
         isInFragmentarium: true,
+        isEnvelope: true,
       },
     ],
     [
@@ -357,6 +358,7 @@ export const fragmentDto: FragmentDto = {
         note: '',
         legacyData: '',
         isInFragmentarium: false,
+        isEnvelope: true,
       },
     ],
   ],
@@ -439,6 +441,7 @@ export const fragment = new Fragment(
         note: '',
         legacyData: '',
         isInFragmentarium: true,
+        isEnvelope: true,
       },
     ],
     [
@@ -450,6 +453,7 @@ export const fragment = new Fragment(
         note: '',
         legacyData: '',
         isInFragmentarium: false,
+        isEnvelope: true,
       },
     ],
   ],