diff --git a/Core/Frameworks/Baikal/Model/Calendar.php b/Core/Frameworks/Baikal/Model/Calendar.php
index dfd0b02..c3e261d 100644
--- a/Core/Frameworks/Baikal/Model/Calendar.php
+++ b/Core/Frameworks/Baikal/Model/Calendar.php
@@ -162,6 +162,18 @@ class Calendar extends \Flake\Core\Model\Db {
 			)
 		)));
 
+        $oMorpho->add(new \Formal\Element\Text(array(
+            "prop" => "calendarcolor",
+            "label" => "Calendar color",
+            "validation" => "color",
+            "popover" => array(
+                    "title" => "Calendar color",
+                    "content" => "This is the color that will be displayed in your CalDAV client.</br>".
+                    "Must be supplied in format '#RRGGBBAA' (alpha channel optional) with hexadecimal values.</br>".
+                    "This value is optional.",
+            )
+        )));
+
 		$oMorpho->add(new \Formal\Element\Text(array(
 			"prop" => "description",
 			"label" => "Description"
diff --git a/Core/Frameworks/Formal/Form.php b/Core/Frameworks/Formal/Form.php
index d9ff63a..5283b2b 100644
--- a/Core/Frameworks/Formal/Form.php
+++ b/Core/Frameworks/Formal/Form.php
@@ -314,6 +314,14 @@ class Form {
 		
 		return TRUE;
 	}
+
+	public function validateColor($sValue, \Formal\Form\Morphology $oMorpho, \Formal\Element $oElement) {
+		if(!empty($sValue) && !preg_match("/^#[a-fA-F0-9]{6}([a-fA-F0-9]{2})?$/", $sValue)) {
+			return "<strong>" . $oElement->option("label") . "</strong> is not a valid color with format '#RRGGBB' or '#RRGGBBAA' in hexadecimal values.";
+		}
+		
+		return TRUE;
+	}
 	
 	public function postValue($sPropName) {
 		$aData = \Flake\Util\Tools::POST("data");