diff --git a/package.json b/package.json
index 4c9c76c..007fec6 100644
--- a/package.json
+++ b/package.json
@@ -52,15 +52,15 @@
     "test": "vitest run"
   },
   "dependencies": {
-    "hyparquet": "1.20.1"
+    "hyparquet": "1.20.2"
   },
   "devDependencies": {
     "@babel/eslint-parser": "7.28.5",
-    "@types/node": "24.9.1",
-    "@vitest/coverage-v8": "4.0.3",
-    "eslint": "9.38.0",
-    "eslint-plugin-jsdoc": "61.1.9",
+    "@types/node": "24.10.1",
+    "@vitest/coverage-v8": "4.0.8",
+    "eslint": "9.39.1",
+    "eslint-plugin-jsdoc": "61.2.0",
     "typescript": "5.9.3",
-    "vitest": "4.0.3"
+    "vitest": "4.0.8"
   }
 }
diff --git a/src/unconvert.js b/src/unconvert.js
index a10cdbc..3df0396 100644
--- a/src/unconvert.js
+++ b/src/unconvert.js
@@ -1,3 +1,4 @@
+import { toJson } from 'hyparquet'
 import { geojsonToWkb } from './wkb.js'
 
 const dayMillis = 86400000 // 1 day in milliseconds
@@ -32,7 +33,7 @@ export function unconvert(element, values) {
   if (ctype === 'JSON') {
     if (!Array.isArray(values)) throw new Error('JSON must be an array')
     const encoder = new TextEncoder()
-    return values.map(v => v === undefined ? undefined : encoder.encode(JSON.stringify(v)))
+    return values.map(v => v === undefined ? undefined : encoder.encode(JSON.stringify(toJson(v))))
   }
   if (ctype === 'UTF8') {
     if (!Array.isArray(values)) throw new Error('strings must be an array')