diff --git a/core/block.js b/core/block.js
index 2b0ce8d34..f462c2f29 100644
--- a/core/block.js
+++ b/core/block.js
@@ -934,9 +934,9 @@ Blockly.Block.prototype.setColour = function(colour) {
   // Set colour just stores these as properties on the block, but never uses
   // them again.
   // TODO: see if we can just get rid of these properties on the block.
-  var parsed = Blockly.blockRendering.Colourer.parseColour(colour);
+  var parsed = Blockly.utils.colour.parseBlockColour(colour);
   this.hue_ = parsed.hue;
-  this.colour_ = parsed.colour;
+  this.colour_ = parsed.hex;
 };
 
 /**
diff --git a/core/block_svg.js b/core/block_svg.js
index 8af8b9e66..98228c024 100644
--- a/core/block_svg.js
+++ b/core/block_svg.js
@@ -68,25 +68,9 @@ Blockly.BlockSvg = function(workspace, prototypeName, opt_id) {
    * @type {Blockly.blockRendering.IPathObject}
    * @package
    */
-  this.pathObject =
-      workspace.getRenderer().makePathObject(this.svgGroup_);
-
-  /**
-   * [colourer description]
-   * @type {[type]}
-   * @package
-   */
-  this.colourer =
-      workspace.getRenderer().makeColourer(this, this.pathObject);
-
-  // The next three paths are set only for backwards compatibility reasons.
-  /**
-   * The dark path of the block.
-   * @type {SVGElement}
-   * @private
-   */
-  this.svgPathDark_ = this.pathObject.svgPathDark || null;
+  this.pathObject = workspace.getRenderer().makePathObject(this.svgGroup_);
 
+  // The next two paths are set only for backwards compatibility reasons.
   /**
    * The primary path of the block.
    * @type {SVGElement}
@@ -1035,7 +1019,6 @@ Blockly.BlockSvg.prototype.dispose = function(healStack, animate) {
   this.svgGroup_ = null;
   this.svgPath_ = null;
   this.svgPathLight_ = null;
-  this.svgPathDark_ = null;
   Blockly.utils.dom.stopTextWidthCache();
 };
 
@@ -1049,7 +1032,7 @@ Blockly.BlockSvg.prototype.applyColour = function() {
     return;
   }
 
-  this.colourer.applyColour(this.isShadow());
+  this.pathObject.applyColour(this.isShadow());
 
   var icons = this.getIcons();
   for (var i = 0; i < icons.length; i++) {
@@ -1314,7 +1297,7 @@ Blockly.BlockSvg.prototype.setDeleteStyle = function(enable) {
  * @return {string} #RRGGBB string.
  */
 Blockly.BlockSvg.prototype.getColour = function() {
-  return this.colourer.getColour();
+  return this.pathObject.primaryColour;
 };
 
 /**
@@ -1323,7 +1306,7 @@ Blockly.BlockSvg.prototype.getColour = function() {
  */
 Blockly.BlockSvg.prototype.setColour = function(colour) {
   Blockly.BlockSvg.superClass_.setColour.call(this, colour);
-  this.colourer.setColour(colour);
+  this.pathObject.setColour(colour);
   this.applyColour();
 };
 
@@ -1339,7 +1322,7 @@ Blockly.BlockSvg.prototype.setStyle = function(blockStyleName) {
 
   if (blockStyle) {
     this.hat = blockStyle.hat;
-    this.colourer.setFromStyle(blockStyle);
+    this.pathObject.setFromStyle(blockStyle);
     this.applyColour();
   } else {
     throw Error('Invalid style name: ' + blockStyleName);
diff --git a/core/field_angle.js b/core/field_angle.js
index 1025824e6..dafed3810 100644
--- a/core/field_angle.js
+++ b/core/field_angle.js
@@ -269,9 +269,9 @@ Blockly.FieldAngle.prototype.showEditor_ = function() {
   var editor = this.dropdownCreate_();
   Blockly.DropDownDiv.getContentDiv().appendChild(editor);
 
-  var colourer = this.sourceBlock_.colourer;
-  Blockly.DropDownDiv.setColour(colourer.getColour(),
-      colourer.getBorderColour());
+  var pathObject = this.sourceBlock_.pathObject;
+  Blockly.DropDownDiv.setColour(pathObject.primaryColour,
+      pathObject.tertiaryColour);
 
   Blockly.DropDownDiv.showPositionedByField(
       this, this.dropdownDispose_.bind(this));
diff --git a/core/field_date.js b/core/field_date.js
index 9ed4f68bd..b6fff8f2c 100644
--- a/core/field_date.js
+++ b/core/field_date.js
@@ -130,8 +130,8 @@ Blockly.FieldDate.prototype.render_ = function() {
  * @package
  */
 Blockly.FieldDate.prototype.applyColour = function() {
-  this.todayColour_ = this.sourceBlock_.colourer.getColour();
-  this.selectedColour_ = this.sourceBlock_.colourer.getShadowColour();
+  this.todayColour_ = this.sourceBlock_.pathObject.primaryColour;
+  this.selectedColour_ = this.sourceBlock_.pathObject.secondaryColour;
   this.updateEditor_();
 };
 
diff --git a/core/field_dropdown.js b/core/field_dropdown.js
index 9c59069f3..179f98e23 100644
--- a/core/field_dropdown.js
+++ b/core/field_dropdown.js
@@ -472,9 +472,9 @@ Blockly.FieldDropdown.prototype.applyColour = function() {
   // Update arrow's colour.
   if (this.sourceBlock_ && this.arrow_) {
     if (this.sourceBlock_.isShadow()) {
-      this.arrow_.style.fill = this.sourceBlock_.colourer.getColourShadow();
+      this.arrow_.style.fill = this.sourceBlock_.pathObject.secondaryColour;
     } else {
-      this.arrow_.style.fill = this.sourceBlock_.colourer.getColour();
+      this.arrow_.style.fill = this.sourceBlock_.pathObject.primaryColour;
     }
   }
 };
diff --git a/core/icon.js b/core/icon.js
index 5b3a28a23..f703beea2 100644
--- a/core/icon.js
+++ b/core/icon.js
@@ -141,7 +141,7 @@ Blockly.Icon.prototype.iconClick_ = function(e) {
  */
 Blockly.Icon.prototype.applyColour = function() {
   if (this.isVisible()) {
-    this.bubble_.setColour(this.block_.colourer.getColour());
+    this.bubble_.setColour(this.block_.pathObject.primaryColour);
   }
 };
 
diff --git a/core/renderers/common/colourer.js b/core/renderers/common/colourer.js
deleted file mode 100644
index 563c0fec3..000000000
--- a/core/renderers/common/colourer.js
+++ /dev/null
@@ -1,131 +0,0 @@
-/**
- * @license
- * Copyright 2019 Google LLC
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/**
- * @fileoverview
- * @author fenichel@google.com (Rachel Fenichel)
- */
-'use strict';
-
-goog.provide('Blockly.blockRendering.Colourer');
-goog.provide('Blockly.blockRendering.IColourer');
-
-goog.require('Blockly.blockRendering.IPathObject');
-
-/**
- * An interface for a block's colourer object.
- * @param {!SVGElement} _root The root SVG element.
- * @interface
- */
-Blockly.blockRendering.IColourer = function(block, pathObject) {};
-
-/**
- * )
- * @param {[type]} block [description]
- * @param {[type]} pathObject [description]
- * @implements {Blockly.blockRendering.IColourer}
- * @constructor
- */
-Blockly.blockRendering.Colourer = function(block, pathObject) {
-  this.block = block;
-  /**
-   * The renderer's path object.
-   * @type {Blockly.blockRendering.IPathObject}
-   * @package
-   */
-  this.pathObject = /** {Blockly.BlockRender.PathObject} */ (pathObject);
-
-  this.svgPath = this.pathObject.svgPath;
-
-  this.hue_;
-  this.colour_;
-  this.colourSecondary_;
-  this.colourTertiary_;
-};
-
-Blockly.blockRendering.Colourer.prototype.applyColours = function(isShadow) {
-  if (isShadow) {
-    this.svgPath.setAttribute('stroke', 'none');
-    this.svgPath.setAttribute('fill', this.colourSecondary_);
-  } else {
-    this.svgPath.setAttribute('stroke', this.colourTertiary_);
-    this.svgPath.setAttribute('fill', this.colour_);
-  }
-};
-
-/**
- * Change the colour of a block.
- * @param {number|string} colour HSV hue value (0 to 360), #RRGGBB string,
- *     or a message reference string pointing to one of those two values.
- */
-Blockly.blockRendering.Colourer.prototype.setColour = function(colour) {
-  console.log('todo: set colour');
-  // this.colour_ = colour;
-  // this.colourSecondary_ = Blockly.utils.colour.blend('#fff', this.colour, 0.6);
-  // this.colourTertiary_ = Blockly.utils.colour.blend('#fff', this.colour, 0.3);
-};
-
-Blockly.blockRendering.Colourer.prototype.setFromStyle = function(blockStyle) {
-  this.parseColour(blockStyle['colourPrimary']);
-  this.colourSecondary_ = blockStyle['colourSecondary'] ||
-      Blockly.utils.colour.blend('#fff', this.colour_, 0.6);
-  this.colourTertiary_ = blockStyle['colourTertiary'] ||
-      Blockly.utils.colour.blend('#fff', this.colour_, 0.3);
-};
-
-Blockly.blockRendering.Colourer.prototype.getBorderColour = function() {
-  return this.colourTertiary_;
-};
-
-Blockly.blockRendering.Colourer.prototype.getShadowColour = function() {
-  return this.colourSecondary_;
-};
-
-/**
- * Change the colour of a block.
- * @param {number|string} colour HSV hue value (0 to 360), #RRGGBB string,
- *     or a message reference string pointing to one of those two values.
- * @return {{hue: ?number, colour: string}} An object containing the colour as
- *     a #RRGGBB string, and the hue if the input was an HSV hue value.
- */
-Blockly.blockRendering.Colourer.parseColour = function(colour) {
-  var dereferenced = (typeof colour == 'string') ?
-      Blockly.utils.replaceMessageReferences(colour) : colour;
-
-  var hue = Number(dereferenced);
-  if (!isNaN(hue) && 0 <= hue && hue <= 360) {
-    return {
-      hue: hue,
-      colour: Blockly.hueToHex(hue)
-    };
-  } else {
-    var hex = Blockly.utils.colour.parse(dereferenced);
-    if (hex) {
-      // Only store hue if colour is set as a hue.
-      return {
-        hue: null,
-        colour: hex
-      };
-    } else {
-      var errorMsg = 'Invalid colour: "' + dereferenced + '"';
-      if (colour != dereferenced) {
-        errorMsg += ' (from "' + colour + '")';
-      }
-      throw Error(errorMsg);
-    }
-  }
-};
diff --git a/core/renderers/common/path_object.js b/core/renderers/common/path_object.js
index 07b1aa343..34d65733b 100644
--- a/core/renderers/common/path_object.js
+++ b/core/renderers/common/path_object.js
@@ -74,6 +74,12 @@ Blockly.blockRendering.PathObject = function(root) {
   this.svgPathDark = Blockly.utils.dom.createSvgElement('path',
       {'class': 'blocklyPathDark', 'transform': 'translate(1,1)'},
       this.svgRoot);
+
+
+  this.hue_;
+  this.primaryColour;
+  this.secondaryColour;
+  this.tertiaryColour;
 };
 
 /**
@@ -95,3 +101,67 @@ Blockly.blockRendering.PathObject.prototype.flipRTL = function() {
   // Mirror the block's path.
   this.svgPath.setAttribute('transform', 'scale(-1 1)');
 };
+
+/**
+ * Apply the stored colours to the block's path, taking into account whether
+ * the paths belong to a shadow block.
+ * @param {boolean} isShadow True if the block is a shadow block.
+ * @package
+ */
+Blockly.blockRendering.PathObject.prototype.applyColour = function(isShadow) {
+  if (isShadow) {
+    this.svgPath.setAttribute('stroke', 'none');
+    this.svgPath.setAttribute('fill', this.secondaryColour);
+  } else {
+    this.svgPath.setAttribute('stroke', this.tertiaryColour);
+    this.svgPath.setAttribute('fill', this.primaryColour);
+  }
+};
+
+/**
+ * Update colour properties based on a triplet of colours.
+ * @param {string} primary The primary colour.
+ * @param {string} secondary The secondary colour, or null to have the colourer
+ *     generate it.
+ * @param {string} tertiary The tertiary colour, or null to have the colourer
+ *     generate it.
+ * @package
+ */
+Blockly.blockRendering.PathObject.prototype.setColourFromTriplet = function(
+    primary, secondary, tertiary) {
+  this.primaryColour = primary;
+  this.secondaryColour = secondary ||
+      Blockly.utils.colour.blend('#fff', primary, 0.6);
+  this.tertiaryColour = tertiary ||
+      Blockly.utils.colour.blend('#fff', primary, 0.3);
+};
+
+/**
+ * Update colour properties based on a single colour value.
+ * @param {number|string} colour HSV hue value (0 to 360), #RRGGBB string,
+ *     or a message reference string pointing to one of those two values.
+ */
+Blockly.blockRendering.PathObject.prototype.setColour = function(colour) {
+  var parsed = Blockly.utils.colour.parseBlockColour(colour);
+  if (parsed.hue) {
+    this.hue_ = parsed.hue;
+  }
+  this.setColourFromTriplet(parsed.hex, null, null);
+};
+
+/**
+ * Update colour properties based on a block style.
+ * @param {!Blockly.Theme.BlockStyle} blockStyle The block style to use.
+ * @package
+ */
+Blockly.blockRendering.PathObject.prototype.setFromStyle = function(
+    blockStyle) {
+  var parsed =
+      Blockly.utils.colour.parseBlockColour(blockStyle['colourPrimary']);
+  if (parsed.hue) {
+    this.hue_ = parsed.hue;
+  }
+  this.setColourFromTriplet(parsed.hex,
+      blockStyle['colourSecondary'],
+      blockStyle['colourTertiary']);
+};
diff --git a/core/renderers/common/renderer.js b/core/renderers/common/renderer.js
index c9d19902e..49a83943a 100644
--- a/core/renderers/common/renderer.js
+++ b/core/renderers/common/renderer.js
@@ -28,8 +28,6 @@ goog.require('Blockly.blockRendering.Drawer');
 goog.require('Blockly.blockRendering.IPathObject');
 goog.require('Blockly.blockRendering.PathObject');
 goog.require('Blockly.blockRendering.RenderInfo');
-goog.require('Blockly.blockRendering.IColourer');
-goog.require('Blockly.blockRendering.Colourer');
 goog.require('Blockly.CursorSvg');
 
 goog.requireType('Blockly.blockRendering.Debug');
@@ -127,18 +125,6 @@ Blockly.blockRendering.Renderer.prototype.makePathObject = function(root) {
   return new Blockly.blockRendering.PathObject(root);
 };
 
-/**
- * Create a new instance of a renderer path object.
- * @param {!Blockly.BlockSvg} block The root SVG element.
- * @param {!Blockly.blockRendering.IPathObject} pathObject [description]
- * @return {!Blockly.blockRendering.IColourer} The renderer path object.
- * @package
- */
-Blockly.blockRendering.Renderer.prototype.makeColourer = function(block,
-    pathObject) {
-  return new Blockly.blockRendering.Colourer(block, pathObject);
-};
-
 /**
  * Get the current renderer's constant provider.  We assume that when this is
  * called, the renderer has already been initialized.
diff --git a/core/renderers/geras/colourer.js b/core/renderers/geras/colourer.js
deleted file mode 100644
index eb8548cd7..000000000
--- a/core/renderers/geras/colourer.js
+++ /dev/null
@@ -1,119 +0,0 @@
-/**
- * @license
- * Copyright 2019 Google LLC
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/**
- * @fileoverview
- * @author fenichel@google.com (Rachel Fenichel)
- */
-'use strict';
-
-goog.provide('Blockly.geras.Colourer');
-
-goog.require('Blockly.geras.PathObject');
-
-
-/**
- * )
- * @param {[type]} block [description]
- * @param {[type]} pathObject [description]
- * @implements {Blockly.blockRendering.IColourer}
- * @constructor
- */
-Blockly.geras.Colourer = function(block, pathObject) {
-  /**
-   * The renderer's path object.
-   * @type {Blockly.geras.PathObject}
-   * @package
-   */
-  this.pathObject = /** {Blockly.geras.PathObject} */ (pathObject);
-
-  this.svgPath = this.pathObject.svgPath;
-  this.svgPathLight = this.pathObject.svgPathLight;
-  this.svgPathDark = this.pathObject.svgPathDark;
-  this.svgPath.setAttribute('stroke', 'none');
-  this.svgPathLight.style.display = '';
-  this.svgPathDark.setAttribute('display', '');
-
-  this.colour_;
-  this.colourTertiary_;
-  this.colourDark_;
-  this.colourSecondary_;
-  this.styleName_;
-};
-
-Blockly.geras.Colourer.prototype.applyColour = function(isShadow) {
-  if (isShadow) {
-    this.svgPathLight.style.display = 'none';
-    this.svgPathDark.setAttribute('fill', this.colourSecondary_);
-    this.svgPath.setAttribute('stroke', 'none');
-    this.svgPath.setAttribute('fill', this.colourSecondary_);
-  } else {
-    this.svgPathLight.style.display = '';
-    this.svgPathDark.style.display = '';
-    this.svgPath.setAttribute('stroke', 'none');
-    this.svgPathLight.setAttribute('stroke', this.colourTertiary_);
-    this.svgPathDark.setAttribute('fill', this.colourDark_);
-    this.svgPath.setAttribute('fill', this.colour_);
-  }
-};
-
-/**
- * Get the colour of a block.
- * @return {string} #RRGGBB string.
- */
-Blockly.geras.Colourer.prototype.getColour = function() {
-  return this.colour_;
-};
-
-Blockly.geras.Colourer.prototype.getShadowColour = function() {
-  return this.colourSecondary_;
-};
-
-Blockly.geras.Colourer.prototype.getBorderColour = function() {
-  return this.colourTertiary_;
-};
-
-Blockly.geras.Colourer.prototype.setColourFromTriplet = function(primary,
-    secondary, tertiary) {
-  this.colour_ = primary;
-  this.colourSecondary_ = secondary ||
-      Blockly.utils.colour.blend('#fff', primary, 0.6);
-  this.colourTertiary_ = tertiary ||
-      Blockly.utils.colour.blend('#fff', primary, 0.3);
-  this.colourDark_ = tertiary ||
-      Blockly.utils.colour.blend('#000', primary, 0.2);
-};
-
-/**
- * Change the colour of a block.
- * @param {number|string} colour HSV hue value (0 to 360), #RRGGBB string,
- *     or a message reference string pointing to one of those two values.
- */
-Blockly.geras.Colourer.prototype.setColour = function(colour) {
-  var primary = Blockly.blockRendering.Colourer.parseColour(colour).colour;
-  this.setColourFromTriplet(primary, null, null);
-};
-
-Blockly.geras.Colourer.prototype.setFromStyle = function(blockStyle) {
-  var primary =
-      Blockly.blockRendering.Colourer.parseColour(blockStyle['colourPrimary'])
-          .colour;
-  this.setColourFromTriplet(primary,
-      blockStyle['colourSecondary'],
-      blockStyle['colourTertiary']);
-};
-
diff --git a/core/renderers/geras/path_object.js b/core/renderers/geras/path_object.js
index 416cb54a9..5fafb4ff3 100644
--- a/core/renderers/geras/path_object.js
+++ b/core/renderers/geras/path_object.js
@@ -34,6 +34,7 @@ goog.require('Blockly.utils.dom');
  * @param {!SVGElement} root The root SVG element.
  * @constructor
  * @implements {Blockly.blockRendering.IPathObject}
+ * @extends {Blockly.blockRendering.PathObject}
  * @package
  */
 Blockly.geras.PathObject = function(root) {
@@ -66,7 +67,16 @@ Blockly.geras.PathObject = function(root) {
    */
   this.svgPathLight = Blockly.utils.dom.createSvgElement('path',
       {'class': 'blocklyPathLight'}, this.svgRoot);
+
+
+  this.hue_;
+  this.primaryColour;
+  this.secondaryColour;
+  this.tertiaryColour;
+  this.darkColour;
 };
+Blockly.utils.object.inherits(Blockly.geras.PathObject,
+    Blockly.blockRendering.PathObject);
 
 /**
  * Set each of the paths generated by the renderer onto the respective SVG element.
@@ -90,3 +100,36 @@ Blockly.geras.PathObject.prototype.flipRTL = function() {
   this.svgPathLight.setAttribute('transform', 'scale(-1 1)');
   this.svgPathDark.setAttribute('transform', 'translate(1,1) scale(-1 1)');
 };
+
+/**
+ * Apply the stored colours to the block's path, taking into account whether
+ * the paths belong to a shadow block.
+ * @param {boolean} isShadow True if the block is a shadow block.
+ * @package
+ */
+Blockly.geras.PathObject.prototype.applyColour = function(isShadow) {
+  if (isShadow) {
+    this.svgPathLight.style.display = 'none';
+    this.svgPathDark.setAttribute('fill', this.secondaryColour);
+    this.svgPath.setAttribute('stroke', 'none');
+    this.svgPath.setAttribute('fill', this.secondaryColour);
+  } else {
+    this.svgPathLight.style.display = '';
+    this.svgPathDark.style.display = '';
+    this.svgPath.setAttribute('stroke', 'none');
+    this.svgPathLight.setAttribute('stroke', this.tertiaryColour);
+    this.svgPathDark.setAttribute('fill', this.darkColour);
+    this.svgPath.setAttribute('fill', this.primaryColour);
+  }
+};
+
+/**
+ * @override
+ */
+Blockly.geras.PathObject.prototype.setColourFromTriplet = function(primary,
+    secondary, tertiary) {
+  Blockly.geras.PathObject.superClass_.setColourFromTriplet.call(this, primary,
+      secondary, tertiary);
+  this.darkColour = tertiary ||
+      Blockly.utils.colour.blend('#000', primary, 0.2);
+};
diff --git a/core/renderers/geras/renderer.js b/core/renderers/geras/renderer.js
index f5745e361..b01597ffd 100644
--- a/core/renderers/geras/renderer.js
+++ b/core/renderers/geras/renderer.js
@@ -26,7 +26,6 @@ goog.provide('Blockly.geras.Renderer');
 goog.require('Blockly.blockRendering');
 goog.require('Blockly.blockRendering.Renderer');
 goog.require('Blockly.geras.ConstantProvider');
-goog.require('Blockly.geras.Colourer');
 goog.require('Blockly.geras.Drawer');
 goog.require('Blockly.geras.HighlightConstantProvider');
 goog.require('Blockly.geras.PathObject');
@@ -107,17 +106,6 @@ Blockly.geras.Renderer.prototype.makePathObject = function(root) {
   return new Blockly.geras.PathObject(root);
 };
 
-/**
- * Create a new instance of a renderer path object.
- * @param {!Blockly.BlockSvg} block The root SVG element.
- * @param {!Blockly.geras.IPathObject} pathObject [description]
- * @return {!Blockly.geras.Colourer} The renderer path object.
- * @package
- */
-Blockly.geras.Renderer.prototype.makeColourer = function(block,
-    pathObject) {
-  return new Blockly.geras.Colourer(block, pathObject);
-};
 
 /**
  * Create a new instance of the renderer's highlight constant provider.
diff --git a/core/utils/colour.js b/core/utils/colour.js
index 928fc935b..08aeae89b 100644
--- a/core/utils/colour.js
+++ b/core/utils/colour.js
@@ -211,3 +211,39 @@ Blockly.utils.colour.names = {
   'white': '#ffffff',
   'yellow': '#ffff00'
 };
+
+/**
+ * Parse a block colour from a number or string, as provided in a block
+ * definition.
+ * @param {number|string} colour HSV hue value (0 to 360), #RRGGBB string,
+ *     or a message reference string pointing to one of those two values.
+ * @return {{hue: ?number, colour: string}} An object containing the colour as
+ *     a #RRGGBB string, and the hue if the input was an HSV hue value.
+ */
+Blockly.utils.colour.parseBlockColour = function(colour) {
+  var dereferenced = (typeof colour == 'string') ?
+      Blockly.utils.replaceMessageReferences(colour) : colour;
+
+  var hue = Number(dereferenced);
+  if (!isNaN(hue) && 0 <= hue && hue <= 360) {
+    return {
+      hue: hue,
+      hex: Blockly.hueToHex(hue)
+    };
+  } else {
+    var hex = Blockly.utils.colour.parse(dereferenced);
+    if (hex) {
+      // Only store hue if colour is set as a hue.
+      return {
+        hue: null,
+        hex: hex
+      };
+    } else {
+      var errorMsg = 'Invalid colour: "' + dereferenced + '"';
+      if (colour != dereferenced) {
+        errorMsg += ' (from "' + colour + '")';
+      }
+      throw Error(errorMsg);
+    }
+  }
+};
diff --git a/tests/blocks/test_blocks.js b/tests/blocks/test_blocks.js
index 6f9e0af33..bf79c2f9d 100644
--- a/tests/blocks/test_blocks.js
+++ b/tests/blocks/test_blocks.js
@@ -29,7 +29,7 @@ Blockly.defineBlocksWithJsonArray([  // BEGIN JSON EXTRACT
     "message0": "stack block",
     "previousStatement": null,
     "nextStatement": null,
-    "style": "math_blocks"
+    "colour": "120"
   },
   {
     "type": "test_basic_dummy",