diff --git a/README.md b/README.md
index c3a9eac..43c312b 100644
--- a/README.md
+++ b/README.md
@@ -245,6 +245,7 @@ interface Heading extends Parent {
 	type: "heading"
 	children: Text[]
 	level: "chapter" | "subheading" | "label"
+	blockIdentifier?: string
 }
 ```
 
@@ -354,6 +355,7 @@ interface ImageSet extends Node {
 	type: "image-set"
 	id: string
 	external picture: ImageSetPicture
+	blockIdentifier?: string
 }
 ```
 
@@ -512,6 +514,7 @@ interface Flourish extends Node {
 	description?: string
 	timestamp?: string
 	external fallbackImage?: Image
+	blockIdentifier?: string
 }
 ```
 
diff --git a/content-tree.d.ts b/content-tree.d.ts
index c6c6a3c..f300dd9 100644
--- a/content-tree.d.ts
+++ b/content-tree.d.ts
@@ -36,6 +36,7 @@ export declare namespace ContentTree {
         type: "heading";
         children: Text[];
         level: "chapter" | "subheading" | "label";
+        blockIdentifier?: string;
     }
     interface Strong extends Parent {
         type: "strong";
@@ -77,6 +78,7 @@ export declare namespace ContentTree {
         type: "image-set";
         id: string;
         picture: ImageSetPicture;
+        blockIdentifier?: string;
     }
     type ImageSetPicture = {
         layoutWidth: string;
@@ -156,6 +158,7 @@ export declare namespace ContentTree {
         description?: string;
         timestamp?: string;
         fallbackImage?: Image;
+        blockIdentifier?: string;
     }
     interface BigNumber extends Node {
         type: "big-number";
@@ -309,6 +312,7 @@ export declare namespace ContentTree {
             type: "heading";
             children: Text[];
             level: "chapter" | "subheading" | "label";
+            blockIdentifier?: string;
         }
         interface Strong extends Parent {
             type: "strong";
@@ -350,6 +354,7 @@ export declare namespace ContentTree {
             type: "image-set";
             id: string;
             picture: ImageSetPicture;
+            blockIdentifier?: string;
         }
         type ImageSetPicture = {
             layoutWidth: string;
@@ -429,6 +434,7 @@ export declare namespace ContentTree {
             description?: string;
             timestamp?: string;
             fallbackImage?: Image;
+            blockIdentifier?: string;
         }
         interface BigNumber extends Node {
             type: "big-number";
@@ -583,6 +589,7 @@ export declare namespace ContentTree {
             type: "heading";
             children: Text[];
             level: "chapter" | "subheading" | "label";
+            blockIdentifier?: string;
         }
         interface Strong extends Parent {
             type: "strong";
@@ -623,6 +630,7 @@ export declare namespace ContentTree {
         interface ImageSet extends Node {
             type: "image-set";
             id: string;
+            blockIdentifier?: string;
         }
         type ImageSetPicture = {
             layoutWidth: string;
@@ -699,6 +707,7 @@ export declare namespace ContentTree {
             flourishType: string;
             description?: string;
             timestamp?: string;
+            blockIdentifier?: string;
         }
         interface BigNumber extends Node {
             type: "big-number";
@@ -842,6 +851,7 @@ export declare namespace ContentTree {
             type: "heading";
             children: Text[];
             level: "chapter" | "subheading" | "label";
+            blockIdentifier?: string;
         }
         interface Strong extends Parent {
             type: "strong";
@@ -883,6 +893,7 @@ export declare namespace ContentTree {
             type: "image-set";
             id: string;
             picture?: ImageSetPicture;
+            blockIdentifier?: string;
         }
         type ImageSetPicture = {
             layoutWidth: string;
@@ -962,6 +973,7 @@ export declare namespace ContentTree {
             description?: string;
             timestamp?: string;
             fallbackImage?: Image;
+            blockIdentifier?: string;
         }
         interface BigNumber extends Node {
             type: "big-number";
diff --git a/content_tree.go b/content_tree.go
index abd6b3d..f568158 100644
--- a/content_tree.go
+++ b/content_tree.go
@@ -103,7 +103,7 @@ type ColumnSettingsItems struct {
 
 type BigNumber struct {
 	Type        string      `json:"type"`
-	Data        interface{} `json:"data,omitempty"`
+	Data       	interface{} `json:"data,omitempty"`
 	Description string      `json:"description,omitempty"`
 	Number      string      `json:"number,omitempty"`
 }
@@ -586,14 +586,15 @@ func (n *Emphasis) GetChildren() []Node {
 }
 
 type Flourish struct {
-	Type          string                 `json:"type"`
-	Data          interface{}            `json:"data,omitempty"`
-	Description   string                 `json:"description,omitempty"`
-	FallbackImage *FlourishFallbackImage `json:"fallbackImage,omitempty"`
-	FlourishType  string                 `json:"flourishType,omitempty"`
-	Id            string                 `json:"id,omitempty"`
-	LayoutWidth   string                 `json:"layoutWidth,omitempty"`
-	Timestamp     string                 `json:"timestamp,omitempty"`
+	Type            string                 `json:"type"`
+	Data            interface{}            `json:"data,omitempty"`
+	Description     string                 `json:"description,omitempty"`
+	FallbackImage   *FlourishFallbackImage `json:"fallbackImage,omitempty"`
+	FlourishType    string                 `json:"flourishType,omitempty"`
+	Id              string                 `json:"id,omitempty"`
+	LayoutWidth     string                 `json:"layoutWidth,omitempty"`
+	Timestamp       string                 `json:"timestamp,omitempty"`
+	BlockIdentifier string                 `json:"blockIdentifier,omitempty"`
 }
 
 func (n *Flourish) GetType() string {
@@ -628,6 +629,7 @@ type Heading struct {
 	Children []*Text     `json:"children,omitempty"`
 	Data     interface{} `json:"data,omitempty"`
 	Level    string      `json:"level,omitempty"`
+	BlockIdentifier string      `json:"blockIdentifier,omitempty"`
 }
 
 func (n *Heading) GetType() string {
@@ -647,10 +649,11 @@ func (n *Heading) GetChildren() []Node {
 }
 
 type ImageSet struct {
-	Type    string      `json:"type"`
-	Data    interface{} `json:"data,omitempty"`
-	ID      string      `json:"id,omitempty"`
-	Picture *Picture    `json:"picture,omitempty"`
+	Type            string      `json:"type"`
+	Data            interface{} `json:"data,omitempty"`
+	ID              string      `json:"id,omitempty"`
+	Picture         *Picture    `json:"picture,omitempty"`
+	BlockIdentifier string      `json:"blockIdentifier,omitempty"`
 }
 
 func (n *ImageSet) GetType() string {
diff --git a/libraries/from-bodyxml/index.js b/libraries/from-bodyxml/index.js
index 344ecc5..488f75e 100644
--- a/libraries/from-bodyxml/index.js
+++ b/libraries/from-bodyxml/index.js
@@ -56,36 +56,44 @@ export let defaultTransformers = {
    * @type {Transformer<ContentTree.transit.Heading>}
    */
   h1(h1) {
+    const blockId = h1.attributes["data-fragment-id"] || h1.attributes["id"];
     return {
       type: "heading",
       level: "chapter",
+      ...(blockId && { blockIdentifier: blockId }),
     };
   },
   /**
    * @type {Transformer<ContentTree.transit.Heading>}
    */
   h2(h2) {
+    const blockId = h2.attributes["data-fragment-id"] || h2.attributes["id"];
     return {
       type: "heading",
       level: "subheading",
+      ...(blockId && { blockIdentifier: blockId }),
     };
   },
   /**
    * @type {Transformer<ContentTree.transit.Heading>}
    */
   h3(h3) {
+    const blockId = h3.attributes["data-fragment-id"] || h3.attributes["id"];
     return {
       type: "heading",
       level: "subheading",
+      ...(blockId && { blockIdentifier: blockId }),
     };
   },
   /**
    * @type {Transformer<ContentTree.transit.Heading>}
    */
   h4(h4) {
+    const blockId = h4.attributes["data-fragment-id"] || h4.attributes["id"];
     return {
       type: "heading",
       level: "label",
+      ...(blockId && { blockIdentifier: blockId }),
     };
   },
   /**
@@ -237,9 +245,11 @@ export let defaultTransformers = {
    * @type {Transformer<ContentTree.transit.ImageSet>}
    */
   [ContentType.imageset](content) {
+    const blockId = content.attributes["data-fragment-id"] || content.attributes["id"];
     return {
       type: "image-set",
       id: content.attributes.url ?? "",
+      ...(blockId && { blockIdentifier: blockId }),
       children: null,
     };
   },
@@ -260,6 +270,7 @@ export let defaultTransformers = {
   [ContentType.content](content) {
     const id = content.attributes.url ?? "";
     const uuid = id.split("/").pop();
+    const blockId = content.attributes["data-fragment-id"] || content.attributes["id"];
 
     if (content.attributes["data-asset-type"] == "flourish") {
       return /** @type {ContentTree.transit.Flourish} */ ({
@@ -271,6 +282,7 @@ export let defaultTransformers = {
         ),
         description: content.attributes["alt"] || "",
         timestamp: content.attributes["data-time-stamp"] || "",
+        ...(blockId && { blockIdentifier: blockId }),
         children: null,
       });
     }
diff --git a/schemas/body-tree.schema.json b/schemas/body-tree.schema.json
index 5f2a150..0f6baad 100644
--- a/schemas/body-tree.schema.json
+++ b/schemas/body-tree.schema.json
@@ -185,6 +185,9 @@
         "ContentTree.transit.Flourish": {
             "additionalProperties": false,
             "properties": {
+                "blockIdentifier": {
+                    "type": "string"
+                },
                 "data": {},
                 "description": {
                     "type": "string"
@@ -217,6 +220,9 @@
         "ContentTree.transit.Heading": {
             "additionalProperties": false,
             "properties": {
+                "blockIdentifier": {
+                    "type": "string"
+                },
                 "children": {
                     "items": {
                         "$ref": "#/definitions/ContentTree.transit.Text"
@@ -247,6 +253,9 @@
         "ContentTree.transit.ImageSet": {
             "additionalProperties": false,
             "properties": {
+                "blockIdentifier": {
+                    "type": "string"
+                },
                 "data": {},
                 "id": {
                     "type": "string"
diff --git a/schemas/content-tree.schema.json b/schemas/content-tree.schema.json
index 4a1114a..a4df50d 100644
--- a/schemas/content-tree.schema.json
+++ b/schemas/content-tree.schema.json
@@ -236,6 +236,9 @@
         "ContentTree.full.Flourish": {
             "additionalProperties": false,
             "properties": {
+                "blockIdentifier": {
+                    "type": "string"
+                },
                 "data": {},
                 "description": {
                     "type": "string"
@@ -328,6 +331,9 @@
         "ContentTree.full.Heading": {
             "additionalProperties": false,
             "properties": {
+                "blockIdentifier": {
+                    "type": "string"
+                },
                 "children": {
                     "items": {
                         "$ref": "#/definitions/ContentTree.full.Text"
@@ -358,6 +364,9 @@
         "ContentTree.full.ImageSet": {
             "additionalProperties": false,
             "properties": {
+                "blockIdentifier": {
+                    "type": "string"
+                },
                 "data": {},
                 "id": {
                     "type": "string"
diff --git a/schemas/transit-tree.schema.json b/schemas/transit-tree.schema.json
index 9864746..aec260d 100644
--- a/schemas/transit-tree.schema.json
+++ b/schemas/transit-tree.schema.json
@@ -210,6 +210,9 @@
         "ContentTree.transit.Flourish": {
             "additionalProperties": false,
             "properties": {
+                "blockIdentifier": {
+                    "type": "string"
+                },
                 "data": {},
                 "description": {
                     "type": "string"
@@ -242,6 +245,9 @@
         "ContentTree.transit.Heading": {
             "additionalProperties": false,
             "properties": {
+                "blockIdentifier": {
+                    "type": "string"
+                },
                 "children": {
                     "items": {
                         "$ref": "#/definitions/ContentTree.transit.Text"
@@ -272,6 +278,9 @@
         "ContentTree.transit.ImageSet": {
             "additionalProperties": false,
             "properties": {
+                "blockIdentifier": {
+                    "type": "string"
+                },
                 "data": {},
                 "id": {
                     "type": "string"